Polymer/layered silicate nanocomposites: a review from preparation to processing

Study curing of epoxy resin by Isophoronediamine/ Triethylenetetramine and reinforced with montmorillonite and effect on compressive strength

Epoxy is a widely used thermosetting resin recognized for its exceptional performance in adhesives, coatings, and various other applications, attributed to its high tensile strength, stiffness, electrical performance, and chemical resistance. Epoxy-clay nanocomposites are extensively employed across diverse industries. The physical and chemical properties of these nanocomposites are influenced by the processing methods, clay modifiers, and curing agents used during their preparation. In this study, epoxy/nanoclay composites based on Diglycidyl Ether Bisphenol-A (DGEBA) will be cross-linked using Isophorone Diamine (IPD), a cycloaliphatic amine, and Triethylenetetramine (TETA), a linear aliphatic amine. The initial phase of the research will assess the impact of different types of cross-linkers, both individually and in combination at various molar ratios (such as Isophorone Diamine: Triethylenetetramine (IPA: TETA) / 25:75 and 75:25), on the compressive strength of the epoxy mortar. In the subsequent phase, the epoxy formulation with an Isophorone Diamine: Triethylenetetramine (IPD: TETA / 75:25), which demonstrates the highest compressive strength, will be selected for further investigation. This formulation will be used to evaluate the effects of different weight percentages (3%, 5%, and 7%) of organically modified montmorillonite (OMMT). The prepared epoxy composites will be characterized using a range of techniques, including Fourier Transform Infrared Spectroscopy (FT-IR), Transmission Electron Microscopy (TEM), and Scanning Electron Microscopy (SEM). The epoxy/nanoclay composite with an IPD: TETA / 75:25 and 3 wt % OMMT is expected to show the highest compressive strength, which is 94 MPa.

The Synthesis of Green Palladium Catalysts Stabilized by Chitosan for Hydrogenation

The proposed paper describes a simple and environmentally friendly method for the synthesis of three-component polymer-inorganic composites, which includes the modification of zinc oxide or montmorillonite (MMT) with chitosan (CS), followed by the immobilization of palladium on the resulting two-component composites. The structures and properties of the obtained composites were characterized by physicochemical methods (IRS, TEM, XPS, SEM, EDX, XRD, BET). Pd-CS species covered the surface of inorganic materials through two different mechanisms. The interaction of chitosan polyelectrolyte with zinc oxide led to the deprotonation of its amino groups and deposition on the surface of ZnO. The immobilization of Pd on CS/ZnO occurred by the hydrolysis of [PdCl4]2-, followed by forming PdO particles by interacting with amino groups of chitosan. In the case of CS/MMT, protonated amino groups of CS interacted with negative sites of MMT, forming a positively charged CS/MMT composite. Furthermore, [PdCl4]2- interacted with the -NH3+ sites of CS/MMT through electrostatic force. According to TEM studies of 1%Pd-CS/ZnO, the presence of Pd nanoclusters composed of smaller Pd nanoparticles of 3-4 nm in size were observed on different sites of CS/ZnO. For 1%Pd-CS/MMT, Pd nanoparticles with sizes of 2 nm were evenly distributed on the support surface. The prepared three-component CS-inorganic composites were tested through the hydrogenation of 2-propen-1-ol and acetylene compounds (phenylacetylene, 2-hexyn-1-ol) under mild conditions (T-40 °C, PH2-1 atm). It was shown that the efficiency of 1%Pd-CS/MMT is higher than that of 1%Pd-CS/ZnO, which can be explained by the formation of smaller Pd particles that are evenly distributed on the support surface. The mechanism of 2-hexyn-1-ol hydrogenation over an optimal 1%Pd-CS/MMT catalyst was proposed.

Chitosan-Clay Mineral Nanocomposites with Antibacterial Activity for Biomedical Application: Advantages and Future Perspectives

Polymers of natural origin, such as representatives of various polysaccharides (e.g., cellulose, dextran, hyaluronic acid, gellan gum, etc.), and their derivatives, have a long tradition in biomedical applications. Among them, the use of chitosan as a safe, biocompatible, and environmentally friendly heteropolysaccharide has been particularly intensively researched over the last two decades. The potential of using chitosan for medical purposes is reflected in its unique cationic nature, viscosity-increasing and gel-forming ability, non-toxicity in living cells, antimicrobial activity, mucoadhesiveness, biodegradability, as well as the possibility of chemical modification. The intuitive use of clay minerals in the treatment of superficial wounds has been known in traditional medicine for thousands of years. To improve efficacy and overcome the ubiquitous bacterial resistance, the beneficial properties of chitosan have been utilized for the preparation of chitosan-clay mineral bionanocomposites. The focus of this review is on composites containing chitosan with montmorillonite and halloysite as representatives of clay minerals. This review highlights the antibacterial efficacy of chitosan-clay mineral bionanocomposites in drug delivery and in the treatment of topical skin infections and wound healing. Finally, an overview of the preparation, characterization, and possible future perspectives related to the use of these advancing composites for biomedical applications is presented.

Strategies for Mitigating Phosphoric Acid Leaching in High-Temperature Proton Exchange Membrane Fuel Cells

High-temperature proton exchange membrane fuel cells (HT-PEMFCs) have become one of the important development directions of PEMFCs because of their outstanding features, including fast reaction kinetics, high tolerance against impurities in fuel, and easy heat and water management. The proton exchange membrane (PEM), as the core component of HT-PEMFCs, plays the most critical role in the performance of fuel cells. Phosphoric acid (PA)-doped membranes have showed satisfied proton conductivity at high-temperature and anhydrous conditions, and significant advancements have been achieved in the design and development of HT-PEMFCs based on PA-doped membranes. However, the persistent issue of HT-PEMFCs caused by PA leaching remains a challenge that cannot be ignored. This paper provides a concise overview of the proton conduction mechanism in HT-PEMs and the underlying causes of PA leaching in HT-PEMFCs and highlights the strategies aimed at mitigating PA leaching, such as designing crosslinked structures, incorporation of hygroscopic nanoparticles, improving the alkalinity of polymers, covalently linking acidic groups, preparation of multilayer membranes, constructing microporous structures, and formation of micro-phase separation. This review will offer a guidance for further research and development of HT-PEMFCs with high performance and longevity.

A QuEChERS method based on octadecyl-bonded hectorite for the determination of ten mycotoxins in yak ghee

To develop a clean-up material suitable for high-fat food matrices for detecting mycotoxins in yak ghee, an octadecyl-bonded hectorite (Hectorite@NHCO(CH2)17CH3) was synthesized through multi-step chemical reactions. A modified QuEChERS-HPLC-MS/MS method for detecting ten mycotoxins in sesame oil in yak ghee was established using Hectorite@NHCO(CH2)17CH3 as clean-up agent. It involved extracting mycotoxin contaminants using acidified acetonitrile and employing the Hectorite@NHCO(CH2)17CH3 to remove interfering substances from the extract. The purified samples were then analyzed using HPLC-MS/MS. Within a linear range of 1.0-500 μg/kg, there was a good linear relationship between the quantification ion peak area of the target analytes and the corresponding concentrations (R2 ≥ 0.9991). The limit of detection (LOD) ranged from 0.10 μg/kg to 18.62 μg/kg and the limit of quantitation (LOQ) ranged 0.32-62.07 μg/kg. The recoveries at low, medium and high concentrations (25, 100 and 500 μg/kg) ranged from 72.2% to 113.9%, with relative standard deviations (RSD) between 3.2% and 17.5%. The intra-day and inter-day precision met experimental requirements. The proposed method was characterized by a high accuracy and precision, and it could cater to the current demand for detecting ten mycotoxins in yak ghee.

A Dynamic Mechanical Analysis on the Compatibilization Effect of Two Different Polymer Waste-Based Compatibilizers in the Fifty/Fifty Polypropylene/Polyamide 6 Blend

This study aims to examine the 50/50 polypropylene/polyamide 6 (iPP/PA6) system molded under confined flow conditions, both in its original state and after being modified by two different interfacial agents. This study provides two main insights. Firstly, it focuses on a polymer blend close to phase inversion. Secondly, it investigates the impact of using two different types of interfacial agents (derived from polymer waste) to enhance the compatibility between iPP and PA6. Dynamic Mechanical Analysis (DMA) has been employed to achieve these objectives. It is important to note that the investigation of the 50/50 iPP/PA6 system is a crucial focus predicted in previous studies, where a series of mechanical properties were evaluated using Box-Wilson design of experiments (DOEs) over the whole compositional range on the iPP/PA6 binary system. Thus, two interfacial modifiers, namely succinic anhydride (SA)-grafted atactic polypropylene with terminal, side, and bridge SA grafts (aPP-SASA) and succinyl-fluoresceine (SF) with bridge succinic anhydride grafting atactic polypropylene (aPP-SFSA), were employed. The authors obtained and characterized these agents. The quantity of these agents used in the blend was identified as a critical coordinate in prior studies conducted by the authors. The processing method used, compression molding under confined conditions, was chosen to minimize any orientation effect on the emerging morphology. All characterization procedures were performed on samples processed by contour machining to retain the blend morphologies as they emerged from the processing stage. Results from WAXS and SAXS synchrotron tests concluded there were no changes in the crystal morphology of the iPP or the PA6 in the blends nor any co-crystallization process throughout the compositional range. These findings, and the long period fits on the PP crystalline phase for the fifty/fifty blends we are discussing, will support the present DMA study. Finally, the efficiency of these interfacial modifiers has been concluded, even in this unfavorable scenario.

Development of starch-cellulose composite films with antimicrobial potential

This study explored the structure and performance of starch-based antibacterial films reinforced with black tea cellulose nanocrystals (BT-CNCs). The optimal addition amount of BT-CNCs is 5 % (w/w Starch). This nanocrystal-infused film, incorporating chitosan (CS), ε-polylysine (ε-PL), and zinc oxide nanoparticles (ZnONP) as antibacterial agents, exhibited a smooth, continuous surface. The addition of BT-CNCs and antibacterial agents did not change the group characteristic peaks of the film, but changed the crystallinity slightly. The films, namely St, St/CNCs, St/CNCs/CS, and St/CNCs/ε-P, maintained high light transmittance (above 80 %), except for the St/CNCs/ZnONP film, which effectively shielded UV radiation. The combined use of antibacterial agents and BT-CNCs enhanced the water and oxygen barrier properties of the film. Notably, the St/CNCs/CS film exhibited the lowest solubility (17.74 % ± 0.36) and the highest tensile strength (14.23 ± 0.16 MPa). The antibacterial efficacy of the films decreased in the order of St/CNCs/ZnONP, St/CNCs/ε-PL, and St/CNCs/CS, with a more pronounced inhibitory effect on E. coli compared to S. aureus. This study marries natural waste recycling with cutting-edge food packaging technology, setting a new benchmark for the development of sustainable packaging materials.

Surface Modification of Calcined Kaolinite for Enhanced Solvent Dispersion and Mechanical Properties in Polybutylene Adipate/Terephthalate Composites

In order to regulate the surface properties of calcined kaolinite for the purpose of achieving uniform distribution within various polar dispersion media, 3-aminopropyltriethoxysilane and phenyl glycidyl ether were employed to chemically modify calcined kaolinite. The grafting rate, surface properties, and dispersion properties of calcined kaolinite particles in different polar organic media were changed by varying the dosage of the modifiers. FT-IR analysis confirmed successful surface modification, while thermogravimetric analysis indicated a maximum graft coverage of 18.44 μmol/m2 for the modified particles. Contact angle measurements and particle size distribution analyses demonstrated the effective adjustment of surface characteristics by the modifiers. Specifically, at a mass ratio of 1.0 of modifier to kaolinite particles, the modified particles exhibited a contact angle of around 125°, achieving uniform dispersion in different polarity media. Particle size distribution ranged from 1600 nm to 2100 nm in cyclohexane and petroleum ether, and from 900 nm to 1200 nm in dioxane, ethyl acetate, and DMF, showcasing a significant improvement in dispersion performance compared to unmodified particles. Concurrently, to improve the mechanical properties of PBAT, modified particles were incorporated into the PBAT matrix, and the effect of modified particle addition on the tensile strength and fracture tensile rate of the composites was investigated. The optimal amount of modified particles is 6 wt.%~8 wt.%. This article aims at synthesizing modifier molecules containing different hydrophilic and hydrophobic groups to chemically graft onto the surface of calcined kaolinite. The hydrophilic and hydrophobic groups on the modified particles can adapt to dispersed systems of different polarities and achieve good distribution within them. The modified particles are added to PBAT to achieve good compatibility and enhance the mechanical properties of the composite material.

Computational Methodologies in Synthesis, Preparation and Application of Antimicrobial Polymers, Biomolecules, and Nanocomposites

The design and optimization of antimicrobial materials (polymers, biomolecules, or nanocomposites) can be significantly advanced by computational methodologies like molecular dynamics (MD), which provide insights into the interactions and stability of the antimicrobial agents within the polymer matrix, and machine learning (ML) or design of experiment (DOE), which predicts and optimizes antimicrobial efficacy and material properties. These innovations not only enhance the efficiency of developing antimicrobial polymers but also enable the creation of materials with tailored properties to meet specific application needs, ensuring safety and longevity in their usage. Therefore, this paper will present the computational methodologies employed in the synthesis and application of antimicrobial polymers, biomolecules, and nanocomposites. By leveraging advanced computational techniques such as MD, ML, or DOE, significant advancements in the design and optimization of antimicrobial materials are achieved. A comprehensive review on recent progress, together with highlights of the most relevant methodologies' contributions to state-of-the-art materials science will be discussed, as well as future directions in the field will be foreseen. Finally, future possibilities and opportunities will be derived from the current state-of-the-art methodologies, providing perspectives on the potential evolution of polymer science and engineering of novel materials.

Full-scale polymer relaxation induced by single-chain confinement enhances mechanical stability of nanocomposites

Polymer nanocomposites with tuning functions are exciting candidates for various applications, and most current research has focused on static mechanical reinforcement. Actually, under service conditions of complex dynamic interference, stable dynamic mechanical properties with high energy dissipation become more critical. However, nanocomposites often exhibit a trade-off between static and dynamic mechanics, because of their contradictory underlying physics between chain crosslinking and chain relaxation. Here, we report a general strategy for constructing ultra-stable dynamic mechanical complex fluid nanocomposites with high energy dissipation by infusing complex fluids into the nanoconfined space. The key is to tailor full-scale polymer dynamics across an exceptionally broad timescale by single-chain confinement. These materials exhibit stable storage modulus (100 ~ 102  MPa) with high energy dissipation (loss factor > 0.4) over a broad frequency range (10-1 ~ 107  Hz)/temperature range (-35 ~ 85°C). In the loss factor > 0.4 region, their dynamic mechanical stability (rate of modulus change versus temperature (k)) is 10 times higher than that of conventional polymer nanocomposites.

Nanocomposite Perfluorosulfonic Acid/Montmorillonite-Na+ Polymer Membrane as Gel Electrolyte in Hybrid Supercapacitors

Solid-state supercapacitors with gel electrolytes have emerged as a promising field for various energy storage applications, including electronic devices, electric vehicles, and mobile phones. In this study, nanocomposite gel membranes were fabricated using the solution casting method with perfluorosulfonic acid (PFSA) ionomer dispersion, both with and without the incorporation of 10 wt.% montmorillonite (MMT). MMT, a natural clay known for its high surface area and layered structure, is expected to enhance the properties of supercapacitor systems. Manganese oxide, selected for its pseudocapacitive behavior in a neutral electrolyte, was synthesized via direct co-precipitation. The materials underwent structural and morphological characterization. For electrochemical evaluation, a two-electrode Swagelok cell was employed, featuring a carbon xerogel negative electrode, a manganese dioxide positive electrode, and a PFSA polymer membrane serving as both the electrolyte and separator. The membrane was immersed in a 1 M Na2SO4 solution before testing. A comprehensive electrochemical analysis of the hybrid cells was conducted and compared with a symmetric carbon/carbon supercapacitor. Cyclic voltammetric curves were recorded, and galvanostatic charge-discharge tests were conducted at various temperatures (20, 40, 60 °C). The hybrid cell with the PFSA/MMT 10 wt.% exhibited the highest specific capacitance and maintained its hybrid profile after prolonged cycling at elevated temperatures, highlighting the potential of the newly developed membrane.

Preparation of Quaternary Ammonium Separation Material based on Coupling Agent Chloromethyl Trimethoxysilane (KH-150) and Its Adsorption and Separation Properties in Studies of Th(IV)

In this research, the authors studied the synthesis of a silicon-based quaternary ammonium material based on the coupling agent chloromethyl trimethoxysilane (KH-150) as well as its adsorption and separation properties for Th(IV). Using FTIR and NMR methods, the silicon-based materials before and after grafting were characterized to determine the spatial structure of functional groups in the silicon-based quaternary ammonium material SG-CTSQ. Based on this, the functional group grafting amount (0.537 mmol·g-1) and quaternization rate (83.6%) of the material were accurately calculated using TGA weight loss and XPS. In the adsorption experiment, the four materials with different grafting amounts showed different degrees of variation in their adsorption of Th(IV) with changes in HNO3 concentration and NO3- concentration but all exhibited a tendency toward anion exchange. The thermodynamic and kinetic experimental results demonstrated that materials with low grafting amounts (SG-CTSQ1 and SG-CTSQ2) tended to physical adsorption of Th(IV), while the other two tended toward chemical adsorption. The adsorption mechanism experiment further proved that the functional groups achieve the adsorption of Th(IV) through an anion-exchange reaction. Chromatographic column separation experiments showed that SG-CTSQ has a good performance in U-Th separation, with a decontamination factor for uranium in Th(IV) of up to 385.1, and a uranium removal rate that can reach 99.75%.

1D and 2D Boron Nitride Nano Structures: A Critical Analysis for Emerging Applications in the Field of Nanocomposites

Boron nitride (BN) with its 1D and 2D nano derivatives have gained immense popularity in both the field of research and applications. These nano derivatives have proved to be one of the most promising fillers which can be incorporated in polymers to form nanocomposites with excellent properties. These materials have been around for 25 years whereas significant research has been done in this field for only the past decade. There are many interesting properties which are imparted to the nanocomposites wherein thermal stability, large energy band gap, resistance to oxidation, excellent thermal conductivity, chemical inertness, and exceptional mechanical properties are just a few worthy of mention. Hexagonal boron nitride (h-BN) was selected as the parent material by most researchers reviewed in this paper through which 2D derivative Boron nitride nanosheets (BNNS) and 1D derivative Boron nitride nanotubes (BNNTs) are synthesized. This review will focus on the in-depth properties of h-BN and further will concisely focus on BNNS and BNNTs for their various properties. A detailed discussion of the addition of BNNS and BNNTs into polymers to form nanocomposites, their synthesis, properties, and applications is followed by a summary determining the most suitable synthesizing processes and the materials, keeping in mind the current challenges.

Electrochemical Impedance Spectroscopy Analysis of Organic Epoxy Coatings Reinforced with Nano Clay

Electrochemical impedance spectroscopy (EIS) is a modern and efficient method for the evaluation of the protective abilities of coatings. However, the interpretation of the experimental data is a difficult task. This paper aims to investigate the effect of the addition of a nano clay, Cloesite 30B®, on the barrier properties of an epoxy-based system through electrochemical impedance spectroscopy in an aerated sodium chloride solution. The EIS spectra of the samples analysed showed different evolutions over time. The subsequent processing of spectra using equivalent electrical circuits is an excellent analytical tool and allows the protective capacity of coatings to be assessed. By using this analysis, it was possible to define and comprehend the impact of adding nano clay in different concentrations to the epoxy resin coating. The work has shown the effectiveness of increasing the barrier effect of the coating with this type of nano clay. However, the improvement is linked to obtaining a correct dispersion of nanoparticles. Otherwise, there is the formation of macro-clusters of particles inside the coating. Their appearance can cause a deterioration in coating performance.

New Methodology for Modifying Sodium Montmorillonite Using DMSO and Ethyl Alcohol

Modified clays with organic molecules have many applications, such as the adsorption of pollutants, catalysts, and drug delivery systems. Different methodologies for intercalating these structures with organic moieties can be found in the literature with many purposes. In this paper, a new methodology of modifying Sodium Montmorillonite clays (Na-Mt) with a faster drying time was investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), BET, and thermogravimetric analysis (TG and DTG). In the modification process, a mixture of ethyl alcohol, DMSO, and Na-Mt were kept under magnetic stirring for one hour. Statistical analysis was applied to evaluate the effects of the amount of DMSO, temperature, and sonication time on the modified clay (DMSO-SMAT) using a 23-factorial design. XRD and FTIR analyses showed the DMSO intercalation into sodium montmorillonite Argel-T (SMAT). An average increase of 0.57 nm for the interplanar distance was found after swelling with DMSO intercalation. BET analysis revealed a decrease in the surface area (from 41.8933 m2/g to 2.1572 m2/g) of Na-Mt when modified with DMSO. The porosity increased from 1.74 (SMAT) to 1.87 nm (DMSO-SMAT) after the application of the methodology. Thermal analysis showed a thermal stability for the DMSO-SMAT material, and this was used to calculate the DMSO-SMAT formula of Na[Al5Mg]Si12O30(OH)6 · 0.54 DMSO. Statistical analysis showed that only the effect of the amount of DMSO was significant for increasing the interlayer space of DMSO-SMAT. In addition, at room temperature, the drying time of the sample using this methodology was 30 min.

In-situ self-reinforcement of amorphous polylactide (PLA) through induced crystallites network and its highly ductile and toughened PLA/poly(butylene adipate-co-terephthalate) (PBAT) blends

Crystallites of a semicrystalline polylactide (cPLA) were induced in an amorphous PLA (aPLA) and its blends with poly(butylene adipate-co-terephthalate) (PBAT) to achieve in-situ self-reinforced PLA based structures. The approach involved the melt blending of cPLA as a minor phase with aPLA and its blends with PBAT at processing temperatures below the crystal melting peak of cPLA. An injection molding (IM) process was first adopted to obtain self-reinforced PLA (SR-PLA) structures at aPLA/cPLA weight ratios of 100/0, 95/5, 90/10, 85/15, and 80/20. IM barrel and mold temperatures revealed crucial impacts on preserving the cPLA crystallites and thereby enhancing the final mechanical performance of SR-PLA (i.e., aPLA/cPLA) samples. SR-PLA samples at various aPLA/cPLA weight ratios of 100/0, 90/10, 80/20, and 70/30 were then melt blended with PBAT to produce SR-PLA/PBAT at a given ratio of 85/15. These blends were first prepared in an internal melt mixer (MM) to evaluate the rheological properties. The rheological analysis confirmed the significance of cPLA reinforcing efficiency within SR-PLA and its corresponding blends with PBAT. Similar SR-PLA/PBAT blends were also prepared using the IM process to explore their thermal and mechanical characteristics. The effect of cPLA concentrations in blends was distinctive, leading to significant enhancements in stain at break and toughness values. This was due to the increased crystallite network within the matrix, further refining PBAT droplets. Morphological analysis of the melt-processed blends through MM and IM also revealed that the PBAT droplets were further refined when the IM process was applied. The induced shear during the molding could have further elongated the cPLA crystallites towards a fiberlike structure, which could additionally cause the matrix viscosity to increase and refine the PBAT droplets.

Colorless and transparent polyimide nanocomposites using organically modified montmorillonite and mica

In this study, we introduce a method for replacing the glass used in existing display electronic materials, lighting, and solar cells by synthesizing a colorless and transparent polyimide (CPI) film with excellent mechanical properties and thermal stability using a combination of new monomers. Poly(amic acid) (PAA) was synthesized using dianhydride 4,4'-biphthalic anhydride (BPA) and diamine 2,2-bis(3-amino-4-hydroxyphenyl) hexafluoropropane (AHP). Various contents of organically modified montmorillonite (MMT) and mica were dispersed in PAA solution through solution intercalation, and then CPI hybrid films were prepared through multi-step thermal imidization. The organoclays synthesized to prepare CPI hybrid films were Cloisite 93A (CS-MMT) and hexadimethrine-mica (HM-Mica) based on MMT and mica, respectively. In particular, the diamine monomer AHP containing a -OH group was selected to increase the dispersibility and compatibility between the hydrophilic clays and the CPI matrix. To demonstrate the characteristics of CPI, the overall polymer structure was bent and a strong electron withdrawing -CF3 group was used as a substituent. The thermomechanical properties, morphology of clay dispersion, and optical transparency of the CPI hybrid films were investigated and compared according to the type and content of organoclays. Two types of organoclays, CS-MMT and HM-Mica, were dispersed in a CPI matrix at 1 to 7 wt%, respectively. In electron microscopy, most of the clays were uniformly dispersed in a plate-like shape of less than 20 nm at a certain critical content of the two types of organoclays, but agglomeration of the clays was observed when the content was higher than the critical content. Hybrids using HM-Mica had better thermomechanical properties and hybrids containing CS-MMT had better optical transparency.

Mechanophysical and Anti-Adhesive Properties of a Nanoclay-Containing PMMA Denture Resin

Poly(methyl methacrylate) (PMMA) is commonly used for dental dentures, but it has the drawback of promoting oral health risks due to oral bacterial adhesion. Recently, various nanoparticles have been incorporated into PMMA to tackle these issues. This study aims to investigate the mechanophysical and antimicrobial adhesive properties of a denture resin by incorporating of nanoclay into PMMA. Specimens were prepared by adding 0, 1, 2, and 4 wt % surface-modified nanoclay (Sigma) to self-polymerizing PMMA denture resin. These specimens were then evaluated using FTIR, TGA/DTG, and FE-SEM with EDS. Various mechanical and surface physical properties, including nanoindentation, were measured and compared with those of pure PMMA. Antiadhesion experiments were conducted by applying a Candida albicans (ATCC 11006) suspension to the surface of the specimens. The antiadhesion activity of C. albicans was confirmed through a yeast-wall component (mannan) and mRNA-seq analysis. The bulk mechanical properties of nanoclay-PMMA composites were decreased compared to those of pure PMMA, while the flexural strength and modulus met the ISO 20795-1 requirement. However, there were no significant differences in the nanoindentation hardness and elastic modulus. The surface energy revealed a significant decrease at 4 wt % nanoclay-PMMA. The antiadhesion effect of Candida albicans was evident along with nanoclay content in the nanocomposites and confirmed by the reduced attachment of mannan on nanoclay-PMMA composites. mRNA-seq analysis supported overall transcriptome changes in altering attachment and metabolism behaviors on the surface. The nanoclay-PMMA materials showed a lower surface energy as the content increased, leading to an antiadhesion effect against Candida albicans. These findings indicate that incorporating nanoclay into PMMA surfaces could be a valuable strategy for preventing the fungal biofilm formation of denture base materials.

The effects of PHB-g-MA types on the mechanical, thermal, morphological, structural, and rheological properties of polyhydroxybutyrate biopolymers

This study investigates the grafting of polyhydroxybutyrate (PHB) chains with maleic anhydride (MA) in concentrations ranging from 5 % to 10 % by weight. This process was conducted during microwave treatment and using a reactive extruder, employing benzoyl peroxide (BPO) as the initiator. The impact of these methods on PHB's overall properties was thoroughly investigated. In the study, PHB-g-MA was incorporated into neat PHB via the extrusion process at a 5 % loading rate. Notably, the mechanical properties exhibited an increase in the presence of PHB-g-MA, likely due to morphological improvements in the neat PHB, as indicated by morphological characterization. X-ray diffraction results indicated crystallinity percentages increase with the addition of MA. Differential scanning calorimetry revealed minimal variation in melting and crystallization temperatures when PHB-g-MA was included. Both storage and loss moduli were enhanced by the incorporation of PHB-g-MA, and the blends exhibited consistent tan delta values. Regarding rheological properties, the storage and loss moduli of PHB blends containing PHB-g-MA blends were observed to rise with rising frequency values. Based on these results, the microwave process was identified as the most effective method for grafting.

Recent Progress of Biodegradable Polymer Package Materials: Nanotechnology Improving Both Oxygen and Water Vapor Barrier Performance

Biodegradable polymers have become a topic of great scientific and industrial interest due to their environmentally friendly nature. For the benefit of the market economy and environment, biodegradable materials should play a more critical role in packaging materials, which currently account for more than 50% of plastic products. However, various challenges remain for biodegradable polymers for practical packaging applications. Particularly pertaining to the poor oxygen/moisture barrier issues, which greatly limit the application of current biodegradable polymers in food packaging. In this review, various strategies for barrier property improvement are summarized, such as chain architecture and crystallinity tailoring, melt blending, multi-layer co-extrusion, surface coating, and nanotechnology. These strategies have also been considered effective ways for overcoming the poor oxygen or water vapor barrier properties of representative biodegradable polymers in mainstream research.

Nano-enabled antimicrobial thin films: design and mechanism of action

Antimicrobial thin films are types of protective coatings that are applied to surfaces such as medical devices, food packaging materials, water-resistant coatings, and other systems. These films prevent and reduce the spread of microbial organisms, including bacteria, fungi, and viruses. Antimicrobial thin films can be prepared from a variety of nanostructured materials including metal nanoparticles, metal oxides, plant materials, enzymes, bacteriocins and polymers. Their antimicrobial mechanism varies mostly based on the types of active agents from which the film is made of. Antimicrobial thin films are becoming increasingly popular microbial treatment methods due to their advantages such as enhanced stability, reduced toxicity levels, extended effectiveness over time and broad spectrum antimicrobial action without side effects on human health or the environment. This popularity and enhanced performance is mainly due to the extended possibility of film designs. Thin films offer convenient formulation methods which makes them suitable for commercial practices aiming at high turnover rates along with residential applications requiring frequent application cycles. This review focuses on recent developments in the possible processing methods and design approaches for assembling the various types of antimicrobial materials into nanostructured thin film-based delivery systems, along with mechanisms of action against microbes.

Linear and nonlinear optical parameters of biodegradable chitosan/polyvinyl alcohol/sodium montmorillonite nanocomposite films for potential optoelectronic applications

Innovations in sophisticated optoelectronic devices have increased interest in high-refractive index polymers. Herein, we report innovative nanocomposite films with high linear and nonlinear refractive indices prepared by casting chitosan (Cs) with polyvinyl alcohol (PVA) (50:50 wt%) along with different concentrations (10-50 wt%) of sodium montmorillonite (NaMMT) nanoclay. The refractive indices in addition to other optical parameters of homopolymers and hybrid materials were investigated by UV-Vis. spectroscopy and optical modeling to assess their potential applications in optics. Besides, the structure, morphology, and thermal stability of the prepared films were investigated by a multitude of experimental techniques including X-ray diffraction (XRD), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), atomic force microscopy (AFM), and thermogravimetric analysis (TGA/DTG). The ATR-FTIR, XRD, SEM, and AFM measurements confirmed the complete exfoliation of NaMMT nanolayers in the Cs/PVA matrix. The TGA/DTG revealed an increase in the thermal stability of Cs/PVA film with increasing clay content. The UV-Vis. measurements revealed a decrease in the optical energy gap (Eg) and a substantial increase in the linear (nD) and nonlinear (n2) refractive indices as clay content increased. Additionally, the nanohybrids displayed low UV transmission and reflected about 80 % of UV rays, making them excellent candidates for UV protection. For the first time, the dissipation factor (tanδ) in the UV/Vis. region has been calculated and fitted with the Drude-Lorentz model to predict the plasma frequency (ωp), resonance frequency (ω0), and electron lifetime (τ) of pristine polymers and nanocomposites.

Environmentally benign approach to formulate nanoclay/starch hydrogel for controlled release of zinc and its application in seed coating of Oryza Sativa plant

Improper use of conventional fertilizers has been linked to adverse effects on soil nutrient levels. To mitigate the negative impact of surface feeding fertilizers and reduce environmental pollution, a new type of seed coating material has been developed to provide nutrients in close proximity to the growing seed. In this study, a biodegradable seed coating film encapsulating micronutrients was fabricated by incorporating montmorillonite into a starch matrix using the melt processing technique. The dispersion of montmorillonite within the starch matrix was examined using X-ray diffraction (XRD), infrared spectroscopy (IR), and thermal gravimetric analysis (TGA). The results revealed polar interactions among starch, silicate layers, and the hydrogel. The XRD analysis demonstrated a shift in the diffraction peak (001) of the Zinc/montmorillonite/starch/glycerol nanocomposite film from 6.2° to 4.9°, indicating the successful intercalation of Zinc, starch, and glycerol. Furthermore, the inclusion of nanoclay improved the thermal stability of the resulting polymer composite and enhanced its ion exchange capacity, water retention, and micronutrient retention. The time-dependent release of zinc micronutrient from the montmorillonite/starch/glycerol composite film was investigated in Zn-deficient soil extract over a 20-day period. The composite film demonstrated extended release behavior of Zn2+. Subsequently, rice seeds were coated with the zinc-containing composite film using a dip-coating method, and their performance in Zn-deficient soil was evaluated. The results indicated that zinc-coated seeds exhibited improved germination percentage, vegetative growth, and yield compared to uncoated seeds.

Elaboration and rheological characterization of nanocomposite hydrogels containing C60 fullerene nanoplatelets

Nanocomposite hydrogels were elaborated that consisted of a physical network formed by an amphiphilic polymer in which C60 fullerene nanoplatelets were embedded. Characterization showed that the nanoplatelets within the polymer network were aggregated. The presence of these nanoplatelets led to an increase of the shear modulus of the hydrogels, that cannot be explained by a filler effect alone. The nanocomposite gels displayed similar rheological behavior, both in linear and non-linear domains, as neat hydrogels at higher polymer concentrations. We suggest that the particles reinforced the gels by forming additional connections between the polymer chains.

Effects of various types of organo-mica on the physical properties of polyimide nanocomposites

Poly(amic acid) (PAA) was synthesized using dianhydride 4,4'-oxydiphthalic anhydride and diamine 3,3'-dihydroxybenzidine, and polyimide (PI) hybrid films were synthesized by dispersing organo-mica in PAA through a solution intercalation method. Hexadimethrine-mica (HM-Mica), 1,2-dimethylhexadecylimidazolium-mica (MI-Mica), and didodecyldiphenylammonium-mica (DP-Mica), which were obtained via the organic modification of pristine mica, were used as the organo-micas for the PI hybrid films. The organo-mica content was varied from 0.5 to 3.0 wt% with respect to the PI matrix. The thermomechanical properties, morphology, and optical transparency of the resultant PI hybrid films were measured and compared. Dispersion of even small amounts of organo-mica effectively improved the physical properties of the PI hybrids, and maximum enhancements in physical properties were observed at a specific critical content. Electron microscopy of the hybrid films revealed that the organo-mica uniformly dispersed throughout the polymer matrix at the nanoscale level when added at low contents but aggregated in the matrix when added at levels above the critical content. Structural changes in the organo-mica closely influenced the changes in the physical properties of the hybrid films. All PI hybrid films with various organo-mica contents showed similar optical properties, but that prepared with MI-Mica demonstrated the best thermomechanical properties. All synthesized PI hybrid films were transparent regardless of the type and content of organo-mica used.

Green Synthesis of Silver Nanoparticles and their Potential Applications in Mitigating Cancer

In recent years, the field of nanotechnology has brought about significant advancements that have transformed the landscape of disease diagnosis, prevention, and treatment, particularly in the realm of medical science. Among the various approaches to nanoparticle synthesis, the green synthesis method has garnered increasing attention. Silver nanoparticles (AgNPs) have emerged as particularly noteworthy nanomaterials within the spectrum of metallic nanoparticles employed for biomedical applications. AgNPs possess several key attributes that make them highly valuable in the biomedical field. They are biocompatible, cost-effective, and environmentally friendly, rendering them suitable for various bioengineering and biomedical applications. Notably, AgNPs have found a prominent role in the domain of cancer diagnosis. Research investigations have provided evidence of AgNPs' anticancer activity, which involves mechanisms such as DNA damage, cell cycle arrest, induction of apoptosis, and the regulation of specific cytokine genes. The synthesis of AgNPs primarily involves the reduction of silver ions by reducing agents. Interestingly, natural products and living organisms have proven to be effective sources for the generation of precursor materials used in AgNP synthesis. This comprehensive review aims to summarize the key aspects of AgNPs, including their characterization, properties, and recent advancements in the field of biogenic AgNP synthesis. Furthermore, the review highlights the potential applications of these nanoparticles in combating cancer.

Structure, rheological properties, and biocompatibility of Laponite® cross-linked starch/polyvinyl alcohol hydrogels

Hydrogels, owing to their unique porous structures, hydrophilic properties, and biocompatibility, are being developed as scaffolds for bone grafts. However, the use of toxic initiators or cross-linking agents is a drawback. To overcome this, we developed Laponite®/cross-linked starch/polyvinyl alcohol (PVA) hydrogels prepared by one-step solution mixing. The structure, rheological properties, and biocompatibility of the hydrogels were investigated. Zeta potential, Fourier transform infrared, and X-ray diffraction analyses showed that hydrogen bonding and electrostatic interactions jointly maintained the structure of the cross-linked hydrogel systems. At a Laponite® concentration of 10 %, the hydrogel with a starch/PVA ratio of 2:2 exhibited a uniform porous structure, the highest storage modulus (G'), and the lowest degradation rate. At a starch/PVA ratio of 2:2, the G' increased; however, the degradation rate decreased with the increase in Laponite® content from 5 % to 20 %. These results indicate that the mechanical strength and degradation rate of the hydrogels could be adjusted by altering the starch/PVA ratio and the amount of Laponite®. In vitro cytotoxicity experiments showed that the Laponite®/starch/PVA (LSP) hydrogels were non-toxic to MC3T3-E1 cells. The starch/PVA ratio had no obvious effect on the proliferation of MC3T3-E1 cells, but an increase in Laponite® content significantly promoted cell proliferation. In summary, the results suggest that these LSP hydrogels have great potential for applications in bone tissue engineering.

Adsorption of Polyetheramine-230 on Expansive Clay and Structure Properties Investigation

Polyetheramine (PEA) is a swelling inhibitor used to address engineering challenges arising from the interaction between montmorillonite (Mt) and water. This study comprehensively investigates the adsorption characteristics of PEA on three representative expansive clay samples: Na-Mt, Ca-Mt, and engineered expansive soil. Additionally, the desorption of exchangeable ions is examined. The findings reveal that a two-stage adsorption kinetic model and a pseudo-second-order kinetic model can properly describe the adsorption kinetics of PEA on expansive clays. PEA exhibits a strong capacity for ion exchange with sodium ions, while the exchange capacity for calcium ions is limited. Both protonated and non-protonated PEA contribute to rapid adsorption processes. The adsorption isotherms are well-fitted by the Langmuir and Freundlich models, with the Langmuir model being reasonable. At lower equilibrium concentrations, a higher proportion of the adsorption amount is attributed to ion exchange compared to higher equilibrium concentrations. Ion exchange emerges as the primary factor contributing to the adsorption of PEA on Na-Mt, whereas the adsorption of PEA on Ca-Mt and expansive soil is primarily attributed to physical adsorption by non-protonated PEA. X-ray diffraction results reveal significant intercalation effects of PEA as they penetrate the interlayer space and hinder interlayer ion hydration. Fourier transform infrared spectrum results demonstrate that the adsorption of PEA minimally impacts the framework of Mt structural units but primarily reduces the adsorbed water content. Clay-PEA composites exhibit a decreased affinity for water. Zeta potential experiments indicate that the adsorption of PEA significantly diminishes the surface potential of clay-PEA composite particles, effectively inhibiting their hydration dispersion.

MXenes vs. clays: emerging and traditional 2D layered nanoarchitectonics

Although MXene materials are considered an emerging research topic, they are receiving considerable interest because, like metals and graphene, they are good electronic conductors but with the particularity that they have a marked hydrophilic character. Having a structural organization and properties close to those of clay minerals (natural silicates typically with a lamellar morphology), they are sometimes referred to as "conducting clays" and exhibit colloidal, surface and intercalation properties also similar to those of clay minerals. The present contribution aims to inform and discuss the nature of MXenes in comparison with clay phyllosilicates, taking into account their structural analogies, outstanding surface properties and advanced applications. The current in-depth understanding of clay minerals may represent a basis for the future development of MXene-derived nanoarchitectures. Comparative examples of the preparation, and studies on the properties and applications of various nanoarchitectures based on clays and MXenes have been included in the present work.

Polysaccharides and proteins based bionanocomposites as smart packaging materials: From fabrication to food packaging applications a review

Food industry is the biggest and rapidly growing industries all over the world. This sector consumes around 40 % of the total plastic produced worldwide as packaging material. The conventional packaging material is mainly petrochemical based. However, these petrochemical based materials impose serious concerns towards environment after its disposal as they are nondegradable. Thus, in search of an appropriate replacement for conventional plastics, biopolymers such as polysaccharides (starch, cellulose, chitosan, natural gums, etc.), proteins (gelatin, collagen, soy protein, etc.), and fatty acids find as an option but again limited by its inherent properties. Attention on the initiatives towards the development of more sustainable, useful, and biodegradable packaging materials, leading the way towards a new and revolutionary green era in the food sector. Eco-friendly packaging materials are now growing dramatically, at a pace of about 10-20 % annually. The recombination of biopolymers and nanomaterials through intercalation composite technology at the nanoscale demonstrated some mesmerizing characteristics pertaining to both biopolymer and nanomaterials such as rigidity, thermal stability, sensing and bioactive property inherent to nanomaterials as well as biopolymers properties such as flexibility, processability and biodegradability. The dramatic increase of scientific research in the last one decade in the area of bionanocomposites in food packaging had reflected its potential as a much-required and important alternative to conventional petroleum-based material. This review presents a comprehensive overview on the importance and recent advances in the field of bionanocomposite and its application in food packaging. Different methods for the fabrication of bionanocomposite are also discussed briefly. Finally, a clear perspective and future prospects of bionanocomposites in food packaging were presented.

Catalytic polymer nanocomposites for environmental remediation of wastewater

The removal of harmful chemicals and species from water, soil, and air is a major challenge in environmental remediation, and a wide range of materials have been studied in this regard. To identify the optimal material for particular applications, research is still ongoing. Polymer nanocomposites (PNCs), which combine the benefits of nanoparticles with polymers, an alternative to conventional materials, may open up new possibilities to overcome this difficulty. They have remarkable mechanical capabilities and compatibility due to their polymer matrix with a very high surface area to volume ratio brought about by their special physical and chemical properties, and the extremely reactive surfaces of the nanofillers. Composites also provide a viable answer to the separation and reuse problems that hinder nanoparticles in routine use. Understanding these PNCs materials in depth and using them in practical environmental applications is still in the early stages of development. The review article demonstrates a crisp introduction to the PNCs with their advantageous properties as a catalyst in environmental remediation. It also provides a comprehensive explanation of the design procedure and synthesis methods for fabricating PNCs and examines in depth the design methods, principles, and design techniques that guide proper design. Current developments in the use of polymer nanocomposites for the pollutant treatment using three commonly used catalytic processes (catalytic and redox degradation, electrocatalytic degradation, and biocatalytic degradation) are demonstrated in detail. Additionally, significant advances in research on the aforementioned catalytic process and the mechanism by which contaminants are degraded are also amply illustrated. Finally, there is a summary of the research challenges and future prospects of catalytic PNCs in environmental remediation.

Polyurea-Graphene Nanocomposites-The Influence of Hard-Segment Content and Nanoparticle Loading on Mechanical Properties

Polyurethane and polyurea-based adhesives are widely used in various applications, from automotive to electronics and medical applications. The adhesive performance depends strongly on its composition, and developing the formulation-structure-property relationship is crucial to making better products. Here, we investigate the dependence of the linear viscoelastic properties of polyurea nanocomposites, with an IPDI-based polyurea (PUa) matrix and exfoliated graphene nanoplatelet (xGnP) fillers, on the hard-segment weight fraction (HSWF) and the xGnP loading. We characterize the material using scanning electron microscopy (SEM) and dynamic mechanical analysis (DMA). It is found that changing the HSWF leads to a significant variation in the stiffness of the material, from about 10 MPa for 20% HSWF to about 100 MPa for 30% HSWF and about 250 MPa for the 40% HSWF polymer (as measured by the tensile storage modulus at room temperature). The effect of the xGNP loading was significantly more limited and was generally within experimental error, except for the 20% HSWF material, where the xGNP addition led to about an 80% increase in stiffness. To correctly interpret the DMA results, we developed a new physics-based rheological model for the description of the storage and loss moduli. The model is based on the fractional calculus approach and successfully describes the material rheology in a broad range of temperatures (-70 °C-+70 °C) and frequencies (0.1-100 s-1), using only six physically meaningful fitting parameters for each material. The results provide guidance for the development of nanocomposite PUa-based materials.

Synthetic Polyisoprene Rubber as a Mimic of Natural Rubber: Recent Advances on Synthesis, Nanocomposites, and Applications

Up to now, rubber materials have been used in a wide range of applications, from automotive parts to special-design engineering pieces, as well as in the pharmaceutical, food, electronics, and military industries, among others. Since the discovery of the vulcanization of natural rubber (NR) in 1838, the continuous demand for this material has intensified the quest for a synthetic substitute with similar properties. In this regard, synthetic polyisoprene rubber (IR) emerged as an attractive alternative. However, despite the efforts made, some properties of natural rubber have been difficult to match (i.e., superior mechanical properties) due not only to its high content of cis-1,4-polyisoprene but also because its structure is considered a naturally occurring nanocomposite. In this sense, cutting-edge research has proposed the synthesis of nanocomposites with synthetic rubber, obtaining the same properties as natural rubber. This review focuses on the synthesis, structure, and properties of natural and synthetic rubber, with a special interest in the synthesis of IR nanocomposites, giving the reader a comprehensive reference on how to achieve a mimic of NR.

Influence of Silicon Additives on Tribological and Rheological Test Results for Vegetable Lubricants

This paper describes an investigation of the effects of silicone-containing additives on the tribological and rheological properties of various lubricant blends. Aerosil® and layered silicate were used to modify lubricants containing rapeseed, linseed and soy oil that were thickened with soap thickener. Tribological tests were carried out using a four-ball concentric contact tester. On the basis of the data obtained from the tribological studies of the selected lubricant blends, it was concluded that the addition of amorphous silica increased the anti-seizure and anti-wear properties of the tested lubricants. The addition of montmorillonite caused a significant increase in the values of the individual parameters determining the level of lubricating properties of the tested lubricants in comparison with the lubricants modified with the silica additive. Based on the results of the rheological tests of the studied lubricants, it was found that the applied additives caused a change in the dynamic viscosity and chemical structure of the tested lubricants, expressed by a change in the values of the G' and G″ indices. The main finding of this manuscript was to demonstrate that the use of montmorillonite and aerosil additives improves the functional properties of vegetable-based plastic lubricants. The performance of tribological and rheological tests is of great scientific importance, as it provides an insight into the interaction of siliceous additives with the results of tribological tests on vegetable-oil-based greases. These findings make it possible to determine the behaviour of the lubricant under load and add to the knowledge of vegetable greases.

Bioactive Materials for Bone Regeneration: Biomolecules and Delivery Systems

Novel tissue regeneration strategies are constantly being developed worldwide. Research on bone regeneration is noteworthy, as many promising new approaches have been documented with novel strategies currently under investigation. Innovative biomaterials that allow the coordinated and well-controlled repair of bone fractures and bone loss are being designed to reduce the need for autologous or allogeneic bone grafts eventually. The current engineering technologies permit the construction of synthetic, complex, biomimetic biomaterials with properties nearly as good as those of natural bone with good biocompatibility. To ensure that all these requirements meet, bioactive molecules are coupled to structural scaffolding constituents to form a final product with the desired physical, chemical, and biological properties. Bioactive molecules that have been used to promote bone regeneration include protein growth factors, peptides, amino acids, hormones, lipids, and flavonoids. Various strategies have been adapted to investigate the coupling of bioactive molecules with scaffolding materials to sustain activity and allow controlled release. The current manuscript is a thorough survey of the strategies that have been exploited for the delivery of biomolecules for bone regeneration purposes, from choosing the bioactive molecule to selecting the optimal strategy to synthesize the scaffold and assessing the advantages and disadvantages of various delivery strategies.

Ultralow Coefficient of Thermal Expansion and a High Colorless Transparent Polyimide Film Realized Through a Reinforced Hydrogen-Bond Network by In Situ Polymerization of Aromatic Polyamide in Colorless Polyimide

Colorless polyimides (CPIs) are a key substrate material for flexible organic light-emitting diode (OLED) displays and have attracted worldwide attention. Here, in this paper, the dispersion and interfacial interaction of aromatic polyamide (PA) in CPI (synthesized from 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) and 2,2'-bis(trifluoromethyl)benzidine (TFMB)) were significantly improved by in situ polymerization, and colorless transparent macromolecular polyimide composites (CPI-PAx) were successfully prepared by PA and CPI. By adjusting the ratio of PA to CPI, a high-performance engineering plastic with excellent film-forming properties was obtained. Molecular simulations confirmed the uniform distribution of PA in CPI and its interaction in polymers. In CPI-PAx, the CPI was locked by the PA chain, and numerous molecular chains were mutually entangled to form a hydrogen-bond network structure. Due to the strong interaction between the chains imparted by the hydrogen bonds of the PA, they do not slide under external forces and heating. In addition, the additive PA has excellent dimensional stability, thermal, and mechanical properties, and CPI has outstanding optical properties, so the synthesized CPI-PAx combines the comprehensive properties of PA and CPI. The CPI-PAx has excellent thermal and mechanical properties, with a thermal decomposition temperature of 499 °C, a glass transition temperature of 385 °C, a coefficient of thermal expansion of 0.8 ppm K-1, a tensile strength of 50.9 MPa, and an elastic modulus of 3.9 GPa. Particularly, CPI-PAx has a 90% transmittance in the visible region. These data prove that the strategy of combining PA and CPI by in situ polymerization is an effective method to circumvent the bottleneck of CPI in the current flexible window application, and this design strategy is universal.

The Study on the Morphology and Compression Properties of Microcellular TPU/Nanoclay Tissue Scaffolds for Potential Tissue Engineering Applications

Thermoplastic polyurethane (TPU) materials have shown promise in tissue engineering applications due to their mechanical properties and biocompatibility. However, the addition of nanoclays to TPU can further enhance its properties. In this study, the effects of nanoclays on the microstructure, mechanical behavior, cytocompatibility, and proliferation of TPU/nanoclay (TPUNC) composite scaffolds were comprehensively investigated. The dispersion morphology of nanoclays within the TPU matrix was examined using transmission electron microscopy (TEM). It was found that the nanoclays exhibited a well-dispersed and intercalated structure, which contributed to the improved mechanical properties of the TPUNC scaffolds. Mechanical testing revealed that the addition of nanoclays significantly enhanced the compressive strength and elastic resilience of the TPUNC scaffolds. Cell viability and proliferation assays were conducted using MG63 cells cultured on the TPUNC scaffolds. The incorporation of nanoclays did not adversely affect cell viability, as evidenced by the comparable cell numbers between nanoclay-filled and unfilled TPU scaffolds. The presence of nanoclays within the TPUNC scaffolds did not disrupt cell adhesion or proliferation. The incorporation of nanoclays improved the dispersion morphology, enhanced mechanical performance, and maintained excellent biocompatibility. These findings suggest that TPUNC composites have great potential for tissue engineering applications, providing a versatile and promising scaffold material for regenerative medicine.

Thermal, Morphological and Mechanical Properties of Multifunctional Composites Based on Biodegradable Polymers/Bentonite Clay: A Review

The extensive use of non-biodegradable plastic products has resulted in significant environmental problems caused by their accumulation in landfills and their proliferation into water bodies. Biodegradable polymers offer a potential solution to mitigate these issues through the utilization of renewable resources which are abundantly available and biodegradable, making them environmentally friendly. However, biodegradable polymers face challenges such as relatively low mechanical strength and thermal resistance, relatively inferior gas barrier properties, low processability, and economic viability. To overcome these limitations, researchers are investigating the incorporation of nanofillers, specifically bentonite clay, into biodegradable polymeric matrices. Bentonite clay is an aluminum phyllosilicate with interesting properties such as a high cation exchange capacity, a large surface area, and environmental compatibility. However, achieving complete dispersion of nanoclays in polymeric matrices remains a challenge due to these materials' hydrophilic and hydrophobic nature. Several methods are employed to prepare polymer-clay nanocomposites, including solution casting, melt extrusion, spraying, inkjet printing, and electrospinning. Biodegradable polymeric nanocomposites are versatile and promising in various industrial applications such as electromagnetic shielding, energy storage, electronics, and flexible electronics. Additionally, combining bentonite clay with other fillers such as graphene can significantly reduce production costs compared to the exclusive use of carbon nanotubes or metallic fillers in the matrix. This work reviews the development of bentonite clay-based composites with biodegradable polymers for multifunctional applications. The composition, structure, preparation methods, and characterization techniques of these nanocomposites are discussed, along with the challenges and future directions in this field.

Highly Orientated Sericite Nanosheets in Epoxy Coating for Excellent Corrosion Protection of AZ31B Mg Alloy

The growing demands for material longevity in marine environments necessitate the development of highly efficient, low-cost, and durable corrosion-protective coatings. Although magnesium alloys are widely used in the automotive and aerospace industries, severe corrosion issues still hinder their long-term service in naval architecture. In the present work, an epoxy composite coating containing sericite nanosheets is prepared on the AZ31B Mg alloy using a one-step electrophoretic deposition method to improve corrosion resistance. Due to the polyetherimide (PEI) modification, positively charged sericite nanosheets can be highly orientated in an epoxy coating under the influence of an electric field. The sericite-incorporated epoxy coating prepared in the emulsion with 4 wt.% sericite exhibits the highest corrosion resistance, with its corrosion current density being 6 orders of magnitude lower than that of the substrate. Electrochemical measurements and immersion tests showed that the highly orientated sericite nanosheets in the epoxy coating have an excellent barrier effect against corrosive media, thus significantly improving the long-term anti-corrosion performance of the epoxy coating. This work provides new insight into the design of lamellar filler/epoxy coatings with superior anticorrosion performance and shows promise in the corrosion protection of magnesium alloys.

Layered Clay Minerals in Cancer Therapy: Recent Progress and Prospects

Cancer is one of the deadliest diseases, and current treatment regimens suffer from limited efficacy, nonspecific toxicity, and chemoresistance. With the advantages of good biocompatibility, large specific surface area, excellent cation exchange capacity, and easy availability, clay minerals have been receiving ever-increasing interests in cancer treatment. They can act as carriers to reduce the toxic side effects of chemotherapeutic drugs, and some of their own properties can kill cancer cells, etc. Compared with other morphologies clays, layered clay minerals (LCM) have attracted more and more attention due to adjustable interlayer spacing, easier ion exchange, and stronger adsorption capacity. In this review, the structure, classification, physicochemical properties, and functionalization methods of LCM are summarized. The state-of-the-art progress of LCM in antitumor therapy is systematically described, with emphasis on the application of montmorillonite, kaolinite, and vermiculite. Furthermore, the property-function relationships of LCM are comprehensively illustrated to reveal the design principles of clay-based antitumor systems. Finally, foreseeable challenges and outlook in this field are discussed.

Valorizing industrial tobacco wastes within natural clays and chitosan nanocomposites for an ecofriendly insecticide

We report the engineering of insecticide films based on two mineral clays, montmorillonite and kaolinite, combined to chitosan and/or cellulose acetate originating from cigarette filter and subsequently impregnated with tobacco essential oil extracted from tobacco dust. Both binary composites, i.e. clay and chitosan or clay and cellulose acetate, and ternary composites containing clay, chitosan and cellulose acetate were prepared and characterized by XRD, DLS, ELS, and IR to investigate the nature of interactions within the composites. The two clay minerals showed different kinds of interaction with chitosan: intercalation in the case of Montmorillonite vs adsorption on the external surface for kaolinite. Secondly, the nicotine release from the composites films at different temperatures was studied by in-situ IR. The Montmorillonite composites, particularly the ternary one, showed a better encapsulation of nicotine which release was limited. Finally, the insecticidal activity of the composites was evaluated against the Tribolium castaneum a common wheat pest. The differences observed between montmorillonite and kaolinite composites were rationalized in relation to the nature of interaction between the components. The fumigant bioassay showed promising insecticidal effects in the case of the ternary composite cellulose acetate/chitosan/montmorillonite. Therefore, these eco-friendly nanocomposites can be used efficiently for the sustainable protection of stored cereals.

Optimizing the Functional Properties of Starch-Based Biodegradable Films

A definitive screening design was used in order to evaluate the effects of starch, glycerol and montmorillonite (MMT) concentrations, as well as the drying temperature, drying tray type and starch species, on packaging film's functional properties. Optimization showed that in order to obtain films with the minimum possible thickness, the maximum elongation at break, the maximum tensile strength, as well as reduced water vapor permeability and low opacity, a combination of factors should be used as follows: 5.5% wt starch concentration, 30% wt glycerol concentration on a dry starch basis, 10.5% wt MMT concentration on a dry starch basis, 45 °C drying temperature, chickpea as the starch species and plexiglass as the drying tray type. Based on these results, starch films were prepared, and fresh minced meat was stored in them for 3 days. It was shown that the incorporation of MMT at 10.5% wt on a dry starch basis in the packaging films led to a decreased mesophilic and psychrotrophic bacteria growth factor compared to commercial packaging. When assessed for their biodegradability, the starch films disintegrated after 10 days of thermophilic incubation under simulated composting conditions. Finally, to prove their handling capability during industrial production, the starch films were rewound in a paper cylinder using an industrial-scale rewinding machine.

Advances in Organic-Inorganic Hybrid Latex Particles via In Situ Emulsion Polymerization

Hybrid latex particles combine the unique properties of inorganic nano/micro particles with the inherent properties of polymers, exhibiting tremendous potential for a variety of applications. Recent years have witnessed an increased interest in the design and preparation of hybrid latex particles with well-defined size, structure and morphology. Due to its simplicity, versatility and environmental friendliness, the in situ (Pickering) emulsion polymerization has been demonstrated to be a powerful approach for the large-scale preparation of hybrid latex particles. In this review, the strategies and applications of in situ (Pickering) emulsion polymerization for the preparation of hybrid latex particles are systematically summarized. A particular focus is placed on the strategies for the preparation of hybrid latex particles with enhanced properties and well-defined core-shell, yolk-shell, multinuclear, raspberry-like, dumbbell-shaped, multipod-like or armored morphologies. We hope that the considerable advances, examples and principles presented in this review can motivate future contributions to provide a deeper understanding of current preparation technologies, develop new processes, and enable further exploitation of hybrid latex particles with outstanding characteristics and properties.

Injection-Molded Isotactic Polypropylene Colored with Green Transparent and Opaque Pigments

Polypropylene (PP) belongs among the most important commodity plastics due to its widespread application. The color of the PP products can be achieved by the addition of pigments, which can dramatically affect its material characteristics. To maintain product consistency (dimensional, mechanical, and optical), knowledge of these implications is of great importance. This study investigates the effect of transparent/opaque green masterbatches (MBs) and their concentration on the physico-mechanical and optical properties of PP produced by injection molding. The results showed that selected pigments had different nucleating abilities, affecting the dimensional stability and crystallinity of the product. The rheological properties of pigmented PP melts were affected as well. Mechanical testing showed that the presence of both pigments increased the tensile strength and Young's modulus, while the elongation at break was significantly increased only for the opaque MB. The impact toughness of colored PP with both MBs remained similar to that of neat PP. The optical properties were well controlled by the dosing of MBs, and were further related to the RAL color standards, as demonstrated by CIE color space analysis. Finally, the selection of appropriate pigments for PP should be considered, especially in areas where dimensional and color stability, as well as product safety, are highly important.

Carbon and Cellulose-Based Nanoparticle-Reinforced Polymer Nanocomposites: A Critical Review

Nanomaterials are currently used for different applications in several fields. Bringing the measurements of a material down to nanoscale size makes vital contributions to the improvement of the characteristics of materials. The polymer composites acquire various properties when added to nanoparticles, increasing characteristics such as bonding strength, physical property, fire retardance, energy storage capacity, etc. The objective of this review was to validate the major functionality of the carbon and cellulose-based nanoparticle-filled polymer nanocomposites (PNC), which include fabricating procedures, fundamental structural properties, characterization, morphological properties, and their applications. Subsequently, this review includes arrangement of nanoparticles, their influence, and the factors necessary to attain the required size, shape, and properties of the PNCs.

Current Applications of Bionanocomposites in Food Processing and Packaging

Nanotechnology advances are rapidly spreading through the food science field; however, their major application has been focused on the development of novel packaging materials reinforced with nanoparticles. Bionanocomposites are formed with a bio-based polymeric material incorporated with components at a nanoscale size. These bionanocomposites can also be applied to preparing an encapsulation system aimed at the controlled release of active compounds, which is more related to the development of novel ingredients in the food science and technology field. The fast development of this knowledge is driven by consumer demand for more natural and environmentally friendly products, which explains the preference for biodegradable materials and additives obtained from natural sources. In this review, the latest developments of bionanocomposites for food processing (encapsulation technology) and food packaging applications are gathered.

Preparation, compatibility and barrier properties of attapulgite/poly (lactic acid)/thermoplastic starch composites

In this study, AT (attapulgite)/PLA/TPS biocomposites and films were prepared by melt blending technique using PLA and TPS as matrix, polyethylene glycol (PEG) as plasticizing modifier of PLA and AT clay as additive. The effect of AT content on the performance of AT/PLA/TPS composites was investigated. The results showed that, as the AT concentration increased, the fracture surface of the composite showed a bicontinuous phase structure when the AT content was 3 wt%. The rheological properties showed that the addition of AT resulted in more significant deformation of the minor phase, which reduced the phase size and led to lower complex viscosity, and more processability from the industrial perspective. The mechanical properties showed that the addition of AT nanoparticles could simultaneously improve the tensile strength and elongation at break of the composites, reaching a maximum at 3 wt% load. The water vapor barrier performance results showed that AT significantly improved the WVP of the film, and the moisture resistance performance was increased by 254 % compared with the PLA/TPS composite film within 5 h. In conclusion, the obtained AT/PLA/TPS biocomposites showed potential in packaging engineering and injection molding products, especially when renewability and full biodegradability of the material are required.

Long-Term Antibacterial Efficacy of Cetylpyridinium Chloride-Montmorillonite Containing PMMA Resin Cement

Despite being able to adhesively restore teeth, adhesives and cement do not possess any anticariogenic protection potential, by which caries recurrence may still occur and reduce the clinical lifetime of adhesive restorations. Several antibacterial agents have been incorporated into dental adhesives and cement to render them anticariogenic. Due to an additional therapeutic effect, such materials are classified as 'dental combination products' with more strict market regulations. We incorporated cetylpyridinium chloride (CPC), often used for oral hygiene applications, into montmorillonite (CPC-Mont), the latter to serve as a carrier for controlled CPC release. CPC-Mont incorporated into tissue conditioner has been approved by the Pharmaceuticals and Medical Devices Agency (PmontMDA) in Japan. To produce a clinically effective dental cement with the antibacterial potential to prevent secondary caries, we incorporated CPC-Mont into PMMA resin cement. We measured the flexural strength, shear bond strength onto dentin, CPC release, and the biofilm-inhibition potential of the experimental CPC-Mont-containing PMMA cement. An 8 and 10 wt% CPC-Mont concentration revealed the antibacterial potential without reducing the mechanical properties of the PMMA cement.

Analysis of Selected Organophosphorus Compounds and Nano-Additives on Thermal, Smoke Properties and Quantities of CO and CO2 of Epoxy Materials

Majority of anthropogenic air pollutants enter the atmosphere as a result of material combustion, industrial production and transport. Fires not only cause air pollution, but also disrupt ecosystems. Knowledge of the flammability parameters and proper flame-retardant modification of materials hinders the origin and spread of a fire, while also protecting against air pollution. The aim of this study was to obtain fire-retardant modifications of the epoxy resin, and then to analyse the effect of the introduced additives on the rate of heat release, the thermokinetic properties and the toxicity of volatile combustible products. The modifiers of the epoxy resin were organophosphorus compounds and aluminium and magnesium hydroxides, with a grain size of 10 nm. The introduced additives were found to be effective flame retardants as they reduced the rate of heat release and the amounts of toxic products of thermal decomposition and combustion. The HRR_max and HRR_av values of all fire-retardant modifications were lower compared to the corresponding HRR values of the unmodified epoxy material.