Sustainable strategies towards better utilization of synthetic polymers

The abstract provides an overview of a study focused on analyzing diverse strategies to achieve sustainable utilization of synthetic polymers through effective waste management. The escalating global consumption of synthetic polymers has precipitated a concerning increase in plastic waste and environmental degradation. To address this challenge, novel materials with specified application goals, such as engineered plastic, have been developed and are intended for recycling and reuse. Despite the reuse and recycling, when plastic gets disposed into the environment, the degradation properties of plastics render a direct disposal hazard, posing a significant environmental threat. To mitigate these issues, the concept of replacing specific monomers of engineered synthetic plastics with bio-alternatives or blending them with other polymers to enhance sustainability and environmental compatibility has emerged. In this study, Acrylonitrile Butadiene Styrene (ABS) plastic is the focal material, and three distinct investigations were conducted. First, replacing ABS plastic's butadiene monomer with natural rubber was explored for its properties and environmental impact. Second, ABS plastic was blended with virgin, recycled, and bio-alternatives of PET (polyethylene terephthalate) and PVC (polyvinyl chloride) polymers. Lastly, recycled ABS blended with recycled PET and PVC was analyzed for mechanical properties. Comparative assessments of these blends were made based on mechanical properties, carbon emissions, and cost-effectiveness. The study determined that the r-ABS/r-PVC (recycled) blend exhibited the most favorable characteristics for practical application.

Degradable Polymeric Bio(nano)materials and Their Biomedical Applications: A Comprehensive Overview and Recent Updates

Degradable polymers (both biomacromolecules and several synthetic polymers) for biomedical applications have been promising very much in the recent past due to their low cost, biocompatibility, flexibility, and minimal side effects. Here, we present an overview with updated information on natural and synthetic degradable polymers where a brief account on different polysaccharides, proteins, and synthetic polymers viz. polyesters/polyamino acids/polyanhydrides/polyphosphazenes/polyurethanes relevant to biomedical applications has been provided. The various approaches for the transformation of these polymers by physical/chemical means viz. cross-linking, as polyblends, nanocomposites/hybrid composites, interpenetrating complexes, interpolymer/polyion complexes, functionalization, polymer conjugates, and block and graft copolymers, are described. The degradation mechanism, drug loading profiles, and toxicological aspects of polymeric nanoparticles formed are also defined. Biomedical applications of these degradable polymer-based biomaterials in and as wound dressing/healing, biosensors, drug delivery systems, tissue engineering, and regenerative medicine, etc., are highlighted. In addition, the use of such nano systems to solve current drug delivery problems is briefly reviewed.

Reducing plastic pollution caused by demersal fisheries

Marine microplastics generated by wear and tear of bottom trawls and demersal seines during their service life is a growing environmental concern that requires immediate attention. In Norway, these fishing gears account for more than 70 % of the landings of demersal fish species, but they are also the leading sources of microplastics generated by fisheries. Because these two fishing gears are widely used around the world, replacing fossil-based non-degradable plastics with more abrasion-resistant materials, including biodegradable polymers, should contribute to the reduction of marine litter and its associated environmental impacts. However, the lack of available recycling techniques and the need for separate collection of biodegradable polymers means that these materials will most likely be incinerated for energy recovery, which is not favourable from a circular economy perspective. Nonetheless, from an environmental perspective the use of such biodegradable polymers in demersal fisheries could still be a better alternative to standard polymer materials.

Study on the Biodegradation of Poly(Butylene Succinate)/Wheat Bran Biocomposites

This paper presents the results of a study investigating the biodegradation of poly(butylene succinate) (PBS)/wheat bran (WB) biocomposites. Injection mouldings were subjected to biodegradation in compost-filled bioreactors under controlled humidity and temperature conditions. The effects of composting time (14, 42 and 70 days) and WB mass content (10%, 30% and 50% wt.) on the structural and thermal properties of the samples were investigated. Measurements were made by infrared spectral analysis, scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis, and gel permeation chromatography. Results demonstrated that both the thermal and structural properties of the samples depended greatly on the biodegradation time. Specifically, their crystallinity degree increased significantly while molecular mass sharply decreased with biodegradation time, whereas their thermal resistance only showed a slight increase. This resulted from enzymatic hydrolysis that led to the breakdown of ester bonds in polymer chains. It was also found that a higher WB content led to a higher mass loss in the biocomposite samples during biodegradation and affected their post-biodegradation properties. A higher bran content increased the degree of crystallinity of the biocomposite samples but reduced their thermal resistance and molecular mass.

Development of Polyhydroxybutyrate-Based Packaging Films and Methods to Their Ultrasonic Welding

This study developed a technical task associated with the formation of welded joints based on biodegradable polymers and their subsequent physicochemical characterization. The primary objective was to establish the effect of the welding process and modification of natural poly(3-hydroxybutyrate) (PHB) with N,N-dibutylundecenoylamide (DBUA) as a plasticizing agent on the structure and properties of PHB-based biopolymer materials as well as the process and structure of welded joints formation using ultrasonic welding technique. The weldability of biodegradable layers based on PHB and PHB/DBUA mixture was ultrasonically welded and optimized using a standard Branson press-type installation. The effect of the DBUA plasticizer and welding process on the structure of PHB-based biodegradable material was investigated using scanning electron microscopy, X-ray diffraction, FT-IR spectroscopy, differential scanning calorimetry, and thermomechanical analysis. The results confirmed that the DBUA acted as an effective plasticizer of PHB, contributing to lower crystallinity of the PHB/DBUA mixture (63%) in relation to the crystallinity degree of pure PHB film (69%). Ultrasonic welding resulted in an additional increase (approximately 8.5%) in the degree of crystallinity in the PHB/DBUA in relation to the initial PHB/DBUA mixture. The significant shift toward lower temperatures of the crystallization and melting peaks of PHB modified with DBUA were observed using DSC concerning pure PHB. The melt crystallization process of PHB was affected by welding treatment, and a shift toward higher temperature was observed compared with the unwelded PHB/DBUA sample. The butt-welded joints of biodegradable PHB/DBUA materials made using the ultrasonic method tested for tensile strength have damaged the area immediately outside the joining surface.

Coir fiber as thermal insulator and its performance as reinforcing material in biocomposite production

Coir is a lignocellulosic natural fiber derived from the coconut's husk, an abundantly found fruit or nut worldwide. This fiber has some unique characteristics, such as its resistance to seawater, microbial attack, high impact, etc. But its low thermal conductivity or high thermal insulating property makes it suitable for being used as insulators in civil engineering sites. On the other hand, the sustainability of a material depends heavily on its environmental impact of the material. For making sustainable materials like biocomposite, there are no options other than using polymers derived from natural renewable sources. Polylactic acid(PLA) is an example of those types of material. And these materials are often being reinforced by fibers like coir for various reasons including improving mechanical properties, reducing the cost of the material, and improving the material's sustainability. Many coir-reinforced sustainable biopolymer composites have already been produced in many pieces of research, which will be discussed in this paper, along with the chemical and physical structure of coir fiber. In addition, this paper will try to focus on the insulating properties of coir and coir-reinforced composites while will also compare some properties of the composites with some commonly used materials based on different parameters to show the suitability of using the coir fiber in heat-insulating applications and to produce sustainable biocomposite materials.

Recent progress and future directions of membranes green polymers for oily wastewater treatment

The preparation, modification and application of green polymers such as poly-lactic acid (PLA), chitosan (CS), and cellulose acetate (CA) for oily wastewater treatment is summed up in this review. Due to the low environmental pollution, good chemical resistivity, high hydrophobicity, and good capacity for water-oil emulsion separation of the presented polymers, it then highlights the various membrane production methods and their role in producing effective membranes, with a focus on recent advances in improving membrane properties through the addition of various Nano materials. As a result, the hydrophilic/hydrophobic properties that are critical in the oil separation mechanism are highlighted. Finally, it looks at the predictions and challenges in oil/water separation and recovery. These ideas are discussed with a focus on modern production methods and oil separation proficiency.

Effects of Hybrid Polymeric Material Based on Polycaprolactone on the Environment

Polymers are of great interest in areas such as agriculture, medicine and pharmacy, the food and cosmetic industries, and the chemical and construction industries. However, many polymers are nonbiodegradable and are not environmentally friendly. They are highly resistant to degradation and therefore can lead to waste disposal problems. In recent years, the interest in the microbial degradation of polymeric materials has grown due to the desire for less waste pollution in the environment. In this study, the biodegradable polymer that was obtained by the ring-opening polymerization of ε-caprolactone (CL) using an aminopropyl-polydimethylsiloxane (APDMS) oligomer and the effects of the polymer towards the growth and development of tomato plants (Lypercosium esculentum) were investigated. The obtained product was characterized using FTIR spectroscopy, NMR spectroscopy, and energy dispersion spectroscopy (EDX) analysis, and the effects of this compound on the evolution of tomato plants (Lypercosium esculentum) were studied. We also studied the biological stability of the product by identifying some of the microorganisms that developed on the surface, given its susceptibility to biodegradation.

In Service Performance of Toughened PHBV/TPU Blends Obtained by Reactive Extrusion for Injected Parts

Moving toward a more sustainable production model based on a circular economy, biopolymers are considered as one of the most promising alternatives to reduce the dependence on oil-based plastics. Polyhydroxybutyrate-co-valerate (PHBV), a bacterial biopolyester from the polyhydroxialkanoates (PHAs) family, seems to be an attractive candidate to replace commodities in many applications such as rigid packaging, among others, due to its excellent overall physicochemical and mechanical properties. However, it presents a relatively poor thermal stability, low toughness and ductility, thus limiting its applicability with respect to other polymers such as polypropylene (PP). To improve the performance of PHBV, reactive blending with an elastomer seems to be a proper cost-effective strategy that would lead to increased ductility and toughness by rubber toughening mechanisms. Hence, the objective of this work was the development and characterization of toughness-improved blends of PHBV with thermoplastic polyurethane (TPU) using hexamethylene diisocyanate (HMDI) as a reactive extrusion agent. To better understand the role of the elastomer and the compatibilizer, the morphological, rheological, thermal, and mechanical behavior of the blends were investigated. To explore the in-service performance of the blends, mechanical and long-term creep characterization were conducted at three different temperatures (−20, 23, 50 °C). Furthermore, the biodegradability in composting conditions has also been tested. The results showed that HMDI proved its efficiency as a compatibilizer in this system, reducing the average particle size of the TPU disperse phase and enhancing the adhesion between the PHBV matrix and TPU elastomer. Although the sole incorporation of the TPU leads to slight improvements in toughness, the compatibilizer plays a key role in improving the overall performance of the blends, leading to a clear improvement in toughness and long-term behavior.

Applications of Starch Biopolymers for a Sustainable Modern Agriculture

Protected cultivation in modern agriculture relies extensively on plastic-originated mulch films, nets, packaging, piping, silage, and various applications. Polyolefins synthesized from petrochemical routes are vastly consumed in plasticulture, wherein PP and PE are the dominant commodity plastics. Imposing substantial impacts on our geosphere and humankind, plastics in soil threaten food security, health, and the environment. Mismanaged plastics are not biodegradable under natural conditions and generate problematic emerging pollutants such as nano-micro plastics. Post-consumed petrochemical plastics from agriculture face many challenges in recycling and reusing due to soil contamination in fulfilling the zero waste hierarchy. Hence, biodegradable polymers from renewable sources for agricultural applications are pragmatic as mitigation. Starch is one of the most abundant biodegradable biopolymers from renewable sources; it also contains tunable thermoplastic properties suitable for diverse applications in agriculture. Functional performances of starch such as physicomechanical, barrier, and surface chemistry may be altered for extended agricultural applications. Furthermore, starch can be a multidimensional additive for plasticulture that can function as a filler, a metaphase component in blends/composites, a plasticizer, an efficient carrier for active delivery of biocides, etc. A substantial fraction of food and agricultural wastes and surpluses of starch sources are underutilized, without harnessing useful resources for agriscience. Hence, this review proposes reliable solutions from starch toward timely implementation of sustainable practices, circular economy, waste remediation, and green chemistry for plasticulture in agriscience

Artificial Ageing, Chemical Resistance, and Biodegradation of Biocomposites from Poly(Butylene Succinate) and Wheat Bran

The results of comprehensive studies on accelerated (artificial) ageing and biodegradation of polymer biocomposites on PBS matrix filled with raw wheat bran (WB) are presented in this paper. These polymer biocomposites are intended for the manufacture of goods, in particular disposable packaging and disposable utensils, which decompose naturally under the influence of biological agents. The effects of wheat bran content within the range of 10–50 wt.% and extruder screw speed of 50–200 min⁻¹ during the production of biocomposite pellets on the resistance of the products to physical, chemical, and biological factors were evaluated. The research included the determination of the effect of artificial ageing on the changes of structural and thermal properties by infrared spectra (FTIR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TG). They showed structural changes—disruption of chains within the ester bond, which occurred in the composition with 50% bran content as early as after 250 h of accelerated ageing. An increase in the degree of crystallinity with ageing was also found to be as high as 48% in the composition with 10% bran content. The temperature taken at the beginning of weight loss of the compositions studied was also lowered, even by 30 °C at the highest bran content. The changes of mechanical properties of biocomposite samples were also investigated. These include: hardness, surface roughness, transverse shrinkage, weight loss, and optical properties: colour and gloss. The ageing hardness of the biocomposite increased by up to 12%, and the surface roughness (R_a) increased by as much as 2.4 µm at the highest bran content. It was also found that ageing causes significant colour changes of the biocomposition (ΔE = 7.8 already at 10% bran content), and that the ageing-induced weight loss of the biocomposition of 0.31–0.59% is lower than that of the samples produced from PBS alone (1.06%). On the other hand, the transverse shrinkage of moldings as a result of ageing turned out to be relatively small, at 0.05%–0.35%. The chemical resistance of biocomposites to NaOH and HCl as well as absorption of polar and non-polar liquids (oil and water) were also determined. Biodegradation studies were carried out under controlled conditions in compost and weight loss of the tested compositions was determined. The weight of samples made from PBS alone after 70 days of composting decreased only by 4.5%, while the biocomposition with 10% bran content decreased by 15.1%, and with 50% bran, by as much as 68.3%. The measurements carried out showed a significant influence of the content of the applied lignocellulosic fillers (LCF) in the form of raw wheat bran (WB) on the examined properties of the biocompositions and the course of their artificial ageing and biodegradation. Within the range under study, the screw speed of the extruder during the production of biocomposite pellets did not show any significant influence on most of the studied properties of the injection mouldings produced from it.

Analysis of Selected Properties of Injection Moulded Sustainable Biocomposites from Poly(butylene succinate) and Wheat Bran

The paper presents a procedure of the manufacturing and complex analysis of the properties of injection mouldings made of polymeric composites based on the poly(butylene succinate) (PBS) matrix with the addition of a natural filler in the form of wheat bran (WB). The scope of the research included measurements of processing shrinkage and density, analysis of the chemical structure, measurements of the thermal and thermo-mechanical properties (Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TG), Heat Deflection Temperature (HDT), and Vicat Softening Temperature (VST)), and measurements of the mechanical properties (hardness, impact strength, and static tensile test). The measurements were performed using design of experiment (DOE) methods, which made it possible to determine the investigated relationships in the form of polynomials and response surfaces. The mass content of the filler and the extruder screw speed during the production of the biocomposite granulate, which was used for the injection moulding of the test samples, constituted the variable factors adopted in the DOE. The study showed significant differences in the processing, thermal, and mechanical properties studied for individual systems of the DOE.

Compatibilization of Starch/Synthetic Biodegradable Polymer Blends for Packaging Applications: A Review

The health and environmental concerns of the usage of non-biodegradable plastics have driven efforts to explore replacing them with renewable polymers. Although starch is a vital renewable polymer, poor water resistivity and thermo-mechanical properties have limited its applications. Recently, starch/synthetic biodegradable polymer blends have captured greater attention to replace inert plastic materials; the question of ‘immiscibility’ arises during the blend preparation due to the mixing of hydrophilic starch with hydrophobic polymers. The immiscibility issue between starch and synthetic polymers impacts the water absorption, thermo-mechanical properties, and chemical stability demanded by various engineering applications. Numerous studies have been carried out to eliminate the immiscibility issues of the different components in the polymer blends while enhancing the thermo-mechanical properties. Incorporating compatibilizers into the blend mixtures has significantly reduced the particle sizes of the dispersed phase while improving the interfacial adhesion between the starch and synthetic biodegradable polymer, leading to fine and homogeneous structures. Thus, Significant improvements in thermo-mechanical and barrier properties and water resistance can be observed in the compatibilized blends. This review provides an extensive discussion on the compatibilization processes of starch and petroleum-based polymer blends.

Fabrication of Novel Functional Cell-Plastic Using Polyvinyl Alcohol: Effects of Cross-Linking Structure and Mixing Ratio of Components on the Mechanical and Thermal Properties

The current system of disposal of plastic materials fabricated from petroleum-based resources causes serious environmental pollution. To solve the problem, a bioplastic called "cell-plastic" is developed, in which unicellular green algal cells serve as a fundamental resource. This approach converts CO2 in the atmosphere directly into plastic products by exploiting the photosynthetic-driven proliferation of algal cells. Herein, cell-plastic films are fabricated using biodegradable and water-soluble polyvinyl alcohol (PVA) as a matrix, in which the effects of a cell-to-matrix mixing ratio and the chemical structure of the matrix on the mechanical and thermal properties are investigated. As a method of the chemical structural change, a cross-linking structure is introduced to the matrix by connecting hydroxy groups of PVA using aldehyde. The tensile tests reveal that the PVA-cell-plastic film maintains the mechanical properties of PVA film. Moreover, a cross-linked cell-plastic film exhibits high water absorption, making it suitable as a functional cell-plastic material.

Are bio-based and biodegradable microplastics impacting for blue mussel (Mytilus edulis)?

The substitution of petrochemical plastics by bio-based and biodegradable plastics are in need of an evaluation for the potential toxic impacts that they can have on marine wildlife. This study aims to assess the toxicological effects of polylactic acid microparticles at two concentrations, 10 and 100 μg/L, during 8 days on the blue mussel, Mytilus edulis. No significant oxidative stress (catalase, glutathione-S-transferase and superoxide dismutase activities), neurotoxicity (acetylcholinesterase), or immunotoxicity (lysosomal membrane stability and acid phosphatase activity) were detectable. The multivariate analysis of metabolomic data allowed us to differentiate the individuals according to the exposure. From the loading plot of OPLS-DA, 48 ions down-regulated in the individuals exposed to microplastics. They were identified based on HRMS data as glycerophospholipids.

A Review: Research Progress in Modification of Poly (Lactic Acid) by Lignin and Cellulose

With the depletion of petroleum energy, the possibility of prices of petroleum-based materials increasing, and increased environmental awareness, biodegradable materials as a kind of green alternative have attracted more and more research attention. In this context, poly (lactic acid) has shown a unique combination of properties such as nontoxicity, biodegradability, biocompatibility, and good workability. However, examples of its known drawbacks include poor tensile strength, low elongation at break, poor thermal properties, and low crystallization rate. Lignocellulosic materials such as lignin and cellulose have excellent biodegradability and mechanical properties. Compounding such biomass components with poly (lactic acid) is expected to prepare green composite materials with improved properties of poly (lactic acid). This paper is aimed at summarizing the research progress of modification of poly (lactic acid) with lignin and cellulose made in in recent years, with emphasis on effects of lignin and cellulose on mechanical properties, thermal stability and crystallinity on poly (lactic acid) composite materials. Development of poly (lactic acid) composite materials in this respect is forecasted.

Enhanced Mechanical Stability and Biodegradability of Ti-Infiltrated Polylactide

Biodegradable polymers have been often used in place of conventional nondegradable polymers for industrial and medical applications. In particular, polylactide (PLA) has been regarded as a popular ecofriendly plastic and has many advantages like good biocompatibility and processability. Yet, it still has some drawbacks in mechanical properties. Here, we prepared Ti-infiltrated PLA by mimicking the gelatinous jaw of a seaworm whose mechanical properties are toggled up and down by the tiny amount of metal ions, expecting to prepare a new type of alternative. Ti induced significant chemical and microstructural changes in the PLA, which led to a notable improvement in the mechanical properties as compared to the neat PLA. The Ti-infiltrated PLA exhibited high resistance to rapid degradation. More importantly, the toxicity assessment demonstrated that the resulting PLA is still biocompatible and nontoxic. Consequently, we proved that the Ti-infiltrated PLA has high mechanical properties comparable to conventional nondegradable polymers and good biocompatibility as well as delayed biodegradability. We anticipate the current Ti-infiltrated PLA to be an ecofriendly replacement of some conventional plastics, which helps preserve a green environment.

Assembly of miscible supramolecular network blends using DDA·AAD hydrogen-bonding interactions of pendent side-chains

Miscible blends of poly(methyl methacrylate) and polystyrene polymers are assembled through triple hydrogen bonding between complementary ureidoimidazole and amidoisocytosine heterodimers.

Improved mechanical performance of self-adhesive resin cement filled with hybrid nanofibers-embedded with niobium pentoxide

OBJECTIVES

In this study hybrid nanofibers embedded with niobium pentoxide (Nb₂O₅) were synthesized, incorporated in self-adhesive resin cement, and their influence on physical-properties was evaluated.

METHODS

Poly(D,L-lactide), PDLLA cotton-wool-like nanofibers with and without silica-based sol-gel precursors were formulated and spun into submicron fibers via solution blow spinning, a rapid fiber forming technology. The morphology, chemical composition and thermal properties of the spun fibers were characterized by field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS) and Fourier-transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC), respectively. Produced fibers were combined with a self-adhesive resin cement (RelyX U200, 3M ESPE) in four formulations: (1) U200 resin cement (control); (2) U200+1wt.% PDLLA fibers; (3) U200+1wt.% Nb₂O₅-filled PDLLA composite fibers and (4) U200+1wt.% Nb₂O₅/SiO₂-filled PDLLA inorganic-organic hybrid fibers. Physical properties were assessed in flexure by 3-point bending (n=10), Knoop microhardness (n=5) and degree of conversion (n=3). Data were analyzed with One-way ANOVA and Tukey's HSD (α=5%).

RESULTS

Composite fibers formed of PDLLA-Nb₂O₅ exhibited an average diameter of ∼250nm, and hybrid PDLLA+Nb₂O₅/SiO₂ fibers were slightly larger, ∼300nm in diameter. There were significant differences among formulations for hardness and flexural strength (p<0.05). Degree of conversion of resin cement was not affected for all groups, except for Group 4 (p<0.05).

SIGNIFICANCE

Hybrid reinforcement nanofibers are promising as fillers for dental materials. The self-adhesive resin cement with PDLLA+Nb₂O₅ and PDLLA+Nb₂O₅/SiO₂ presented superior mechanical performance than the control group.

Polylactic acid: synthesis and biomedical applications

Social and economic development has driven considerable scientific and engineering efforts on the discovery, development and utilization of polymers. Polylactic acid (PLA) is one of the most promising biopolymers as it can be produced from nontoxic renewable feedstock. PLA has emerged as an important polymeric material for biomedical applications on account of its properties such as biocompatibility, biodegradability, mechanical strength and process ability. Lactic acid (LA) can be obtained by fermentation of sugars derived from renewable resources such as corn and sugarcane. PLA is thus an eco-friendly nontoxic polymer with features that permit use in the human body. Although PLA has a wide spectrum of applications, there are certain limitations such as slow degradation rate, hydrophobicity and low impact toughness associated with its use. Blending PLA with other polymers offers convenient options to improve associated properties or to generate novel PLA polymers/blends for target applications. A variety of PLA blends have been explored for various biomedical applications such as drug delivery, implants, sutures and tissue engineering. PLA and their copolymers are becoming widely used in tissue engineering for function restoration of impaired tissues due to their excellent biocompatibility and mechanical properties. The relationship between PLA material properties, manufacturing processes and development of products with desirable characteristics is described in this article. LA production, PLA synthesis and their applications in the biomedical field are also discussed.

Nanofiller Reinforced Biodegradable PLA/PHA Composites: Current Status and Future Trends

The increasing demand for environmental protection has led to the rapid development of greener and biodegradable polymers, whose creation provided new challenges and opportunities for the advancement of nanomaterial science. Biodegradable polymer materials and even nanofillers (e.g., natural fibers) are important because of their application in greener industries. Polymers that can be degraded naturally play an important role in solving public hazards of polymer materials and maintaining ecological balance. The inherent shortcomings of some biodegradable polymers such as weak mechanical properties, narrow processing windows, and low electrical and thermal properties can be overcome by composites reinforced with various nanofillers. These biodegradable polymer composites have wide-ranging applications in different areas based on their large surface area and greater aspect ratio. Moreover, the polymer composites that exploit the synergistic effect between the nanofiller and the biodegradable polymer matrix can lead to enhanced properties while still meeting the environmental requirement. In this paper, a broad review on recent advances in the research and development of nanofiller reinforced biodegradable polymer composites that are used in various applications, including electronics, packing materials, and biomedical uses, is presented. We further present information about different kinds of nanofillers, biodegradable polymer matrixes, and their composites with specific concern to our daily applications.

Suitability of a PLCL fibrous scaffold for soft tissue engineering applications: A combined biological and mechanical characterisation

Poly(lactide-co-ε-caprolactone) (PLCL) has been reported to be a good candidate for tissue engineering because of its good biocompatibility. Particularly, a braided PLCL scaffold (PLL/PCL ratio = 85/15) has been recently designed and partially validated for ligament tissue engineering. In the present study, we assessed the in vivo biocompatibility of acellular and cellularised scaffolds in a rat model. We then determined its in vitro biocompatibility using stem cells issued from both bone marrow and Wharton Jelly. From a biological point of view, the scaffold was shown to be suitable for tissue engineering in all these cases. Secondly, while the initial mechanical properties of this scaffold have been previously reported to be adapted to load-bearing applications, we studied the evolution in time of the mechanical properties of PLCL fibres due to hydrolytic degradation. Results for isolated PLCL fibres were extrapolated to the fibrous scaffold using a previously developed numerical model. It was shown that no accumulation of plastic strain was to be expected for a load-bearing application such as anterior cruciate ligament tissue engineering. However, PLCL fibres exhibited a non-expected brittle behaviour after two months. This may involve a potential risk of premature failure of the scaffold, unless tissue growth compensates this change in mechanical properties. This combined study emphasises the need to characterise the properties of biomaterials in a pluridisciplinary approach, since biological and mechanical characterisations led in this case to different conclusions concerning the suitability of this scaffold for load-bearing applications.

Perspective highlights on biodegradable polymeric nanosystems for targeted therapy of solid tumors

Introduction: Polymeric nanoparticles (NPs) formulated using biodegradable polymers offer great potential for development of de novo drug delivery systems (DDSs) capable of delivering a wide range of bioactive agents. They can be engineered as advanced multifunctional nanosystems (NSs) for simultaneous imaging and therapy known as theranostics or diapeutics.

Methods: A brief prospective is provided on biomedical importance and applications of biodegradable polymeric NSs through reviewing the recently published literature.

Results: Biodegradable polymeric NPs present unique characteristics, including: nanoscaled structures, high encapsulation capacity, biocompatibility with non-thrombogenic and non-immunogenic properties, and controlled-/sustained-release profile for lipophilic and hydrophilic drugs. Once administered in vivo, all classes of biodegradable polymers (i.e., synthetic, semi-synthetic, and natural polymers) are subjected to enzymatic degradation; and hence, transformation into byproducts that can be simply eliminated from the human body. Natural and semi-synthetic polymers have been shown to be highly stable, much safer, and offer a non-/less-toxic means for specific delivery of cargo drugs in comparison with synthetic polymers. Despite being biocompatible and enzymatically-degradable, there are some drawbacks associated with these polymers such as batch to batch variation, high production cost, structural complexity, lower bioadhesive potential, uncontrolled rate of hydration, and possibility of microbial spoilage. These pitfalls have bolded the importance of synthetic counterparts despite their somewhat toxicity.

Conclusion: Taken all, to minimize the inadvertent effects of these polymers and to engineer much safer NSs, it is necessary to devise biopolymers with desirable chemical and biochemical modification(s) and polyelectrolyte complex formation to improve their drug delivery capacity in vivo.

Thermoplastic starch–polyethylene blends homogenised using deep eutectic solvents

Deep eutectic solvents are shown to be effective modifiers to enable polyethylene to be blended with starch to make a plastic with which can be more easily degraded.

Controlled biodegradation of polymers using nanoparticles and its application

Controlled biodegradation mechanism has been revealed using different nanoparticles which eventually regulate pH of media.

Poly(butylene succinate-co-butylene adipate)/cellulose nanocrystal composites modified with phthalic anhydride

As a kind of biomass nanofiller for polymers, cellulose nanocrystal (CNC) has good mechanical properties and reinforcing capability. To improve the compatibility of poly(butylene succinate-co-butylene adipate) (PBSA)/CNC composites, phthalic anhydride was used as a compatilizer during melt mixing, leading to the significant improvement of the mechanical properties and thermal stability of the composites, which is related to the better dispersion of CNC in the composites. The addition of phthalic anhydride could accelerate the crystallization of PBSA component as evidenced by the curves of isothermal crystallization of the composites, but had little effect on the crystalline polymorphs of PBSA component. The addition of phthalic anhydride could strongly improve the hydrophobicity of the composites. The good mechanical properties, fast crystallization and improved hydrophobicity of PBSA/CNC composites with phthalic anhydride are favor to their practical commercial utilization.

Titanium pyridonates for the homo- and copolymerization of rac-lactide and ε-caprolactone

A series of titanium pyridonate complexes have been synthesized under very mild reaction conditions from a common precursor, Ti(NMe₂)₄. These complexes have been explored as initiators for the ring-opening polymerization of rac-lactide and ε-caprolactone and have proven to be competitive with leading titanium initiators.