Sugar palm nanofibrillated cellulose (Arenga pinnata (Wurmb.) Merr): Effect of cycles on their yield, physic-chemical, morphological and thermal behavior

Comparison of different drying technologies for kiwifruit pomace: Changes in physical characteristics, nutritional properties and antioxidant capacities

The objective of this study was to evaluate the impacts of different drying technologies including microwave drying (MD), vacuum microwave drying (VMD), sun drying (SD), vacuum drying (VD), hot air drying (HAD), and vacuum freeze drying (VFD) on the physical characteristics, nutritional properties and antioxidant capacities of kiwifruit pomace in order to realize by-product utilization and improve energy efficiency. Results showed that both MD and VMD significantly reduced drying time by >94.6%, compared to traditional thermal drying which took 14-48 h. MD exhibited the highest content of soluble dietary fiber (9.5%) and the lowest energy consumption. Furthermore, VMD resulted in the highest content of vitamin C (198.78 mg/100 g) and reducing sugar (73.78%), and the antioxidant capacities ranked only second to VFD. Given the financial advantages and product quality, VMD was suggested to be advantageous technology in actual industrial production.

Strategy to Antibacterial, High-Mechanical, and Degradable Polylactic Acid/Chitosan Composite Film through Reactive Compatibilization via Epoxy Chain Extender

Research into the production of antibacterial, high strength, and environmentally friendly biobased films for use in food packaging is crucial due to growing concerns about food safety. Herein, the preparation of antibacterial, high mechanical, and degradable Polylactic acid/chitosan (PLA/CS) composite films with exceptional interfacial compatibility through reactive compatibilization via the epoxy chain extender ADR4468 is reported. A strong bond, in the form of a chemical bond between PLA and CS, is established by the cycloaddition opening reaction of ADR, which induces cross-linking between hydroxyl and carboxyl groups on the molecular chains. As a result, the elongation at break increased by 31.8% compared to the composite film without ADR. In addition, the composite films exhibited good compost degradability, with a mass reduction of 42-45% after 100 days of degradation.

Effect of post-heat treatment on the UV transmittance, hydrophobicity, and tensile properties of PVA/Uncaria gambir extract blend films

The physical and mechanical properties of biopolymers can be improved by heating technologies. In this research, we improved the properties of Polyvinyl alcohol (PVA)/Uncaria gambir extract (UGE) blend films by post-heating method. After post-heating, the blend film exhibited higher resistance to UV light and improved contact angle performance, while water vapor permeability and moisture absorption decreased. The tensile strength and toughness of the PVA/UGE blend film with a post-heating duration of 40 min were 68.8 MPa and 57.7 MPa, respectively, an increase of 131 % and 127 %, compared to films without post-heating. This facile and cost-effective fabrication method, with environmentally friendly properties, can be applied to biodegradable PVA/UGE blend films to achieve desired properties for optical devices or food packaging materials.

Innovative ionic liquid pretreatment followed by wet disk milling treatment provides enhanced properties of sugar palm nano-fibrillated cellulose

In order to accommodate the increased demand for innovative materials, intensive research has focused on natural resources. In pursuit of advanced substances that exhibit functionality, sustainability, recyclability, and cost-effectiveness, the present work attempted an alternative study on cellulose nanofibers derived from sugar palm fiber. Leveraging an innovative approach involving ionic liquid (IL) pre-treatment, bleaching, and wet disc mill technique, nano-fibrillated cellulose (NFC) was successfully obtained from the sugar palm fiber source. Remarkably, 96.89% of nanofibers were extracted from the sugar palm fiber, demonstrating the process's efficacy and scalability. Further investigation revealed that the sugar palm nano-fibrillated cellulose (SPNFC) exhibited a surface area of 3.46 m2/g, indicating a significant interface for enhanced functionality. Additionally, the analysis unveiled an average pore size of 4.47 nm, affirming its suitability for various applications that necessitate precise filtration. Moreover, the surface charge densities of SPNFC were found to be -32.1 mV, offering opportunities for surface modification and enhanced interactions with various materials. The SPNFC exhibit remarkable thermal stability, enduring temperatures of up to 360.5 °C. Additionally, the isolation process is evident in a significant rise in the crystallinity index, escalating from 50.97% in raw fibers to 61.62% in SPNFC. These findings shed light on the vast potential and distinct features of SPNFC, opening the path for its application in a wide array of industries, including but not limited to advanced materials, biomedicine, and environmental engineering.

Dissolution behavior of ionic liquids for different ratios of lignin and cellulose in the preparation of nanocellulose/lignin blends

Lignin is regarded as a potential solution for boosting the strength of cellulose-based products. However, the mechanism of co-solubilization for lignin and cellulose has not been investigated. In this study, the effect of lignin content on the interaction between lignin and nanocellulose during lignin/cellulose co-dissolution was examined. The results revealed that lignin binds to nanocellulose throughout the dissolution process to limit the degradation of cellulose and to prepare nanocellulose/lignin composites. Moreover, the S units in lignin were more likely to interact with cellulose during the dissolution process, whereas the G units were more likely to condense. However, when the lignin content exceeded 30 wt%, the excess lignin created a severe condensation reaction, which led to a decrease in the lignin content bound to cellulose, resulting in an unequal dissolution of cellulose. Thus, a small amount of lignin attached to cellulose during the co-dissolution of lignin and cellulose inhibits cellulose degradation and can be utilized to create nanocellulose/lignin to extend the potential applications of nanocellulosic materials.

From macro- to nano- scales: Effect of fibrillary celluloses from okara on performance of edible starch film

Starch/cellulose composite is one of the most promising systems since both matrix and reinforce agent have same chemical unite glucose, which results in an excellent compatibility. In this work, edible starch film was developed by compositing starch with diverse fibrillary celluloses (FCs) derived from okara, employing a confluence of chemical interactions and mechanical influences. Since diameter of the FCs can be easily controlled by processing methodologies, it is the first time to systematically investigate the effect of diameter of the FCs from macro to nano-scales on the performances of starch-based film. The fabricated macro- and nano-fibrillar celluloses and reinforced starch films were characterized by scanning electron microscope, optical microscopy, Fourier transform infrared spectroscopy, Rheometer and contact angle. Results showed that the FCs increased modulus (about 170 %) and tensile strength (about 180 %) significantly as expected since they are well-compatible and some chemical interactions. It was found that nano-fibrillary celluloses (CNFs) improve the toughness (about 20 %) of the starch film more efficiently, which improved the well-recognized weakness of starch-based materials. The nano-scale roughness on the surface of the starch film caused by different shrinkage ratios between starch and CNFs during drying reduced water sensitivity, which is another well-recognized weakness of starch film.

Effect of durian peel fiber on thermal, mechanical, and biodegradation characteristics of thermoplastic cassava starch composites

This study is focused on developing and enhancing the properties of durian peel fiber (DPF) reinforced thermoplastic cassava starch (TPCS) composites. The proposed DPF was extracted from agro-waste and incorporated into TPCS with various contents of DPF (10, 20, 30, 40, and 50 wt%) via compression molding. The mechanical and thermal characteristics of the fabricated composites were studied. The thermal properties of the biocomposite were improved with the addition of DPF, as evidenced by an increase in the material's thermal stability and indicated by a higher onset decomposition temperature. The integration of DPF into TPCS improved the biodegradation rate process of the composites. Besides, the results indicated that incorporating DPF in TPCS composites enhanced tensile and flexural properties, with a 40 wt% DPF content exhibited the highest modulus and strength. The tensile and flexural strengths of TPCS/DPF composites were raised significantly from 2.96 to 21.89 MPa and 2.5 to 35.0 MPa, respectively, compared to the control TPCS sample, as DPF increased from 0 to 40 wt%. This finding was consistent with Fourier-Transform Infrared (FT-IR) spectroscopy and scanning electron micrograph (SEM), which showed good interaction between DPF and TPCS matrix. The analysis revealed that DPF at a 40 wt% ratio was the best composition compared to the other ratio. Finally, based on improved results, DPF was identified as a potential resource of green reinforcement for the biodegradable TPCS matrix.

Lignocellulosic Bionanomaterials for Biosensor Applications

The rapid population growth, increasing global energy demand, climate change, and excessive use of fossil fuels have adversely affected environmental management and sustainability. Furthermore, the requirements for a safer ecology and environment have necessitated the use of renewable materials, thereby solving the problem of sustainability of resources. In this perspective, lignocellulosic biomass is an attractive natural resource because of its abundance, renewability, recyclability, and low cost. The ever-increasing developments in nanotechnology have opened up new vistas in sensor fabrication such as biosensor design for electronics, communication, automobile, optical products, packaging, textile, biomedical, and tissue engineering. Due to their outstanding properties such as biodegradability, biocompatibility, non-toxicity, improved electrical and thermal conductivity, high physical and mechanical properties, high surface area and catalytic activity, lignocellulosic bionanomaterials including nanocellulose and nanolignin emerge as very promising raw materials to be used in the development of high-impact biosensors. In this article, the use of lignocellulosic bionanomaterials in biosensor applications is reviewed and major challenges and opportunities are identified.

Crafting two-dimensional materials for contrast agents, drug, and heat delivery applications through green technologies

The development of two-dimensional (2D) materials for biomedical applications has accelerated exponentially. Contrary to their bulk counterparts, the exceptional properties of 2D materials make them highly prospective for contrast agents for bioimage, drug, and heat delivery in biomedical treatment. Nevertheless, empty space in the integration and utilisation of 2D materials in living biological systems, potential toxicity, as well as required complicated synthesis and high-cost production limit the real application of 2D materials in those advance medical treatments. On the other hand, green technology appears to be one of strategy to shed a light on the blurred employment of 2D in medical applications, thus, with the increasing reports of green technology that promote advanced technologies, here, we compile, summarise, and synthesise information on the biomedical technology of 2D materials through green technology point of view. Beginning with a fundamental understanding, of crystal structures, the working mechanism, and novel properties, this article examines the recent development of 2D materials. As well as 2D materials made from natural and biogenic resources, a recent development in green-related synthesis was also discussed. The biotechnology and biomedical-related application constraints are also discussed. The challenges, solutions, and prospects of the so-called green 2D materials are outlined.

Improved production of bacterial cellulose using Gluconacetobacter sp. LYP25, a strain developed in UVC mutagenesis with limited viability conditions

Bacterial cellulose (BC), a natural polymer synthesized by bacteria, has received considerable attention owing to its impressive physicomechanical properties. However, the low productivity of BC-producing strains poses a challenge to industrializing this material and making it economically viable. In the present study, UV-induced random mutagenesis of Gluconacetobacter xylinus ATCC 53524 was performed to improve BC production. Sixty mutants were obtained from the following mutagenesis procedure: the correlation between UVC fluence and cell death was investigated, and a limited viability condition was determined as a UVC dose to kill 99.99 %. Compared to the control strain, BC production by the mutant strains LYP25 and LYP23 improved 46.4 % and 44.9 %, respectively. Fermentation profiling using the selected strains showed that LYP25 was superior in glucose consumption and BC production, 13.8 % and 41.0 %, respectively, compared to the control strain. Finally, the physicochemical properties of LYP25-derived BC were similar to those of the control strain; thus, the mutant strain is expected to be a promising producer of BC in the bio-industry based on improved productivity.

Effect of Wood Dust Fibre Treatments Reinforcement on the Properties of Recycled Polypropylene Composite (r-WoPPC) Filament for Fused Deposition Modelling (FDM)

The efficacy of wood dust fibre treatment on the property of wood dust reinforced recycled polypropylene composite (r-WoPPC) filament was investigated. The wood dust fibre was treated using alkali, silane, and NaOH-silane. The treated wood fibre was incorporated with r-PP using a twin-screw extruder to produce filament. The silane treatment on wood dust fibre enhances interfacial bonding between wood fibre and recycled PP; hence, a filament has the highest wire pull strength, which is 35.2% higher compared to untreated and alkaline-treated wood dust filament. It is because silanol in silane forms a siloxane bond that acts as a coupling agent that improves interfacial bonding between wood dust fibre and recycled PP. The SEM micrograph of the fracture structure reveals that treated silane has strong interfacial bonding between wood dust fibre and recycled PP, having minimal void, gap, and good fibre adhesion. The water absorption test results indicate that filament with treated wood dust absorbs less water than filament with untreated wood because the treatment minimizes the gap between wood fibres and recycled PP. The FTIR analysis identified the presence of silane on the wood dust surface for silane-treated wood dust. The DSC studies suggest that the temperature range 167-170 °C be used in the extrusion machine to produce r-WoPPC filament. As a result, r-WoPPc filaments containing silane-treated wood dust have better mechanical properties and have a greater potential for usage in FDM applications.

Effect of Agar on the Mechanical, Thermal, and Moisture Absorption Properties of Thermoplastic Sago Starch Composites

Thermoplastic starch is a material that has the potential to be environmentally friendly and biodegradable. However, it has certain drawbacks concerning its mechanical performance and is sensitive to the presence of moisture. The current study assessed agar-containing thermoplastic sago starch (TPSS) properties at various loadings. Variable proportions of agar (5%, 10%, and 15% wt%) were used to produce TPSS by the hot-pressing method. Then, the samples were subjected to characterisation using scanning electron microscopy (SEM), mechanical analysis, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), and moisture absorption tests. The results demonstrated that adding agar to starch-based thermoplastic blends significantly improved their tensile, flexural, and impact properties. The samples' morphology showed that the fracture had become more erratic and uneven after adding agar. FT-IR revealed that intermolecular hydrogen bonds formed between TPSS and agar. Moreover, with an increase in agar content, TPSS's thermal stability was also increased. However, the moisture absorption values among the samples increased slightly as the amount of agar increased. Overall, the proposed TPSS/agar blend has the potential to be employed as biodegradable material due to its improved mechanical characteristics.

Recent Developments in Cassava (Manihot esculenta) Based Biocomposites and Their Potential Industrial Applications: A Comprehensive Review

The rapid use of petroleum resources coupled with increased awareness of global environmental problems associated with the use of petroleum-based plastics is a major driving force in the acceptance of natural fibers and biopolymers as green materials. Because of their environmentally friendly and sustainable nature, natural fibers and biopolymers have gained significant attention from scientists and industries. Cassava (Manihot esculenta) is a plant that has various purposes for use. It is the primary source of food in many countries and is also used in the production of biocomposites, biopolymers, and biofibers. Starch from cassava can be plasticized, reinforced with fibers, or blended with other polymers to strengthen their properties. Besides that, it is currently used as a raw material for bioethanol and renewable energy production. This comprehensive review paper explains the latest developments in bioethanol compounds from cassava and gives a detailed report on macro and nano-sized cassava fibers and starch, and their fabrication as blend polymers, biocomposites, and hybrid composites. The review also highlights the potential utilization of cassava fibers and biopolymers for industrial applications such as food, bioenergy, packaging, automotive, and others.

Material Properties of Traditional Handmade Paper Samples Fabricated from Cellulosic Fiber of Lokta Bushes

Handmade papers (HPs) are fabricated from fibrous biomass of Lokta bushes and other plant species following traditional eco-friendly method in Nepal. Although HP fabricated from Lokta bushes is believed to be durable and resistant to bugs and molds, material properties of this paper are not reported in literature. In this study, we measured several material properties of 10 handmade Lokta paper samples collected from local enterprises and paper industries. The mean caliper, grammage, apparent density, equilibrium moisture content, Cobb 60, brightness, opacity, tensile strength, and tensile index values in the paper samples ranged from ∼90 to 700 μm, 50 to 150 g/m², 0.2 to 0.4 g/cm³, 4 to 7%, 50 to 400 g/m², 56 to 67%, 83 to 98%, 30 to 2900 N/m, and 1 to 27 Nm/g, respectively. These properties suggested that the HPs are lightweight papers with intermediate to high strength. The tensile strength was found to be significantly higher along the length direction (p < 0.05). Characteristic features of cellulose, hemicellulose, and lignin were observed in FTIR spectra. The crystalline and amorphous phases were also identified in X-ray diffraction (XRD) data. Electron microscopy images revealed a nicely cross-linked network of intact fibers having almost parallel arrangement of microfibrils. These features could provide strength and durability to the paper samples. Understanding the material properties of HPs down to the sub-microscopic level may help improve the paper quality and find novel applications in the future.

Fibre-Reinforced Polymer Composites: Mechanical Properties and Applications

"Fibre-Reinforced Polymer Composites: Mechanical Properties and Applications" is a newly open Special Issue of Polymers, which aims to publish original and review papers on new scientific and applied research and make boundless contributions to the finding and understanding of the reinforcing effects of various synthetic and natural fibres on the performance of biopolymer composites [...]

The measurement of molecular interactions, structure and physical properties of okara cellulose composite hydrogels using different analytical methods

BACKGROUND

Aiming to address the practical problems of a low utilization rate and the serious waste of soybean residue, novel composite hydrogels based on okara cellulose before and after 2,2,6,6-tetramethylpiperidine oxide (TEMPO) oxidation and high polymers of chitosan (CH), carrageenan (CA) or Arabic gum (AG) were prepared by a homogeneous mixture in ionic liquid.

RESULTS

In the present study, composite hydrogels fabricated from okara cellulose and CH, CA or AG were prepared by dissolving them in an ionic liquid, followed by heating (100 °C, 3 h) and then soaking them in a 1:1 water-isopropanol solution. The composite hydrogels prepared from TEMPO oxidation-treated cellulose were physically cross-linked to CH, CA or AG. The results showed that the intramolecular hydrogen bonds in the amorphous regions of the cellulose were disrupted, whereas the intermolecular hydrogen bonds between the biopolymers were increased, which promoted the formation of composite gels with crystalline structures. The TEMPO treatment increased the gel strength. For example, for the cellulose/CA gels, the hardness, fracturability, springiness and cohesiveness values were 5.9-, 4.3-, 2.4- and 3.6-fold higher compared to the non-treated ones, respectively. The composite hydrogels exhibited good thermal stability, swelling properties and mechanical properties. These novel composite polysaccharide-based hydrogels may therefore have great potential in various food and non-food fields.

CONCLUSION

In summary, the addition of polymers (CH, CA or AG) and TEMPO oxidized cellulose was suitable for increasing the swelling, textural properties, thermal stability and rheological properties of hydrogels, which provides new ideas and new methods for the preparation of bio-based composite hydrogels. © 2022 Society of Chemical Industry.

Isolation and Properties of Cellulose Nanocrystals Fabricated by Ammonium Persulfate Oxidation from Sansevieria trifasciata Fibers

Cellulose nanocrystals (CNCs) were successfully prepared from Sansevieria trifasciata fibers (STFs) via ammonium persulfate (APS) oxidation in this study. The influences of the APS concentration (1.1, 1.5, and 1.9 M) and oxidation temperature (60, 70, and 80 °C) on the characteristics of CNCs were studied. The resulting CNCs were characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). The TEM observations revealed that the rod-like CNCs possessed average length and diameter ranges of 96 to 211 nm and 5 to 13 nm, respectively, which led to an aspect ratio range of 16–19. The optimum conditions for maximum crystallinity were achieved at an oxidation temperature of 70 °C, a reaction time of 16 h, and an APS concentration of 1.5 M. All CNCs exhibited lower thermal stability compared to the STFs. The CNCs could be produced from the STFs through the APS oxidation process and showed potential as nanocomposite reinforcement materials.

Drying and rewetting induce changes in biofilm characteristics and the subsequent release of metal ions

Drying and rewetting can markedly influence the microbial structure and function of river biofilm communities and potentially result in the release of metal ions from biofilms containing metals. However, little information is available on the response of metal-enriched biofilms to drying and rewetting over time. In this study, natural biofilms were allowed to develop in four rotating annular bioreactors for 2-11 weeks, followed by drying for 5 days and rewetting for another 5 days. Subsequently, we assessed Zn, Cd, and As desorption from the biofilms and other related parameters (microbial community structure, biofilm morphology, enzyme activity, and surface components as well as characteristics). High-throughput sequencing of the 16 S rRNA gene and confocal laser scanning microscopy revealed that the biofilm architecture and bacterial communities were distinct in different growth phases and under drying and rewetting conditions (permutational multivariate analysis of variance; p = 0.001). Proteobacteria was the dominant bacterial phylum, accounting for 69.7-90.1% of the total content. Kinetic experiments revealed that the drying and rewetting process increased metal desorption from the biofilm matrix. The desorption of heavy metals was affected by the age of the biofilm, with the maximum amount of metal ions released from 2-week-old biofilms (one-way ANOVA, Zn: p < 0.001; Cd: p = 0.008; As: p < 0.001). The modifications in biofilm properties and decreased diversity of the bacterial community (paired t-test, p < 0.05) after drying and rewetting decreased the number of specific binding sites for metal ions. In addition, negatively charged arsenate and other anions in the liquid phase could compete with As ions for adsorption sites to promote the release of As(V) and/or reductive desorption of As(III). The results of this study and their interpretation are expected to help refine the behaviors of heavy metals in the aquatic environment.

Sugar Palm Fibre-Reinforced Polymer Composites: Influence of Chemical Treatments on Its Mechanical Properties

In the era of globalisation, decreasing synthetic resources, especially petroleum, have encouraged global communities to apply biomass waste as a substitute material for green technology development. The development of plastic products from lignocellulosic fibre-reinforced composites has been a hot topic among material scientists and engineers due to their abundance, sustainable in nature, and less toxic towards health. For the Malaysian scenario, sugar palm is a plant found in the wild and locally planted in certain areas in Malaysia and Indonesia. Generally, sugar palm can be harvested for traditional foods, fruits, starch sugar (gula kabung), and alcohol, whereas sugar palm fibre (SPF) is used in conventional products (brushes and brooms). Various researchers are working on the characterisation of fibre and its composites for engineering and packaging products. The main drawback of SPF is its hydrophilic behaviour, which leads to high moisture uptake and inhibits a good bond between the fibre and the matrix. Thus, a solution for this problem is by implementing chemical treatments on the fibre. From the literature review, no comprehensive review paper has been published on the influence of chemical treatment on the mechanical behaviour of SPF-reinforced polymer composites. Thus, the present review examines recent studies on the mechanical properties of sugar palm lignocellulosic fibres with various chemical treatments to evaluate their potential in structural applications.

Study on the Characteristics of the Dispersion and Conductivity of Surfactants for the Nanofluids

Given the importance of nanofluid dispersion and stability, a number of approaches were proposed and applied to the nanofluid preparation process. Among these approaches, the noncovalent chemical process was intensively utilized because of its effective dispersion ability. For the noncovalent dispersion method, polymers and surfactants are typically used. In order to find an effective noncovalent dispersion method, several types of solutions were prepared in this study. The widely used naturally cellulose nanocrystal (CNC) aqueous solution was compared with several surfactant aqueous solutions. The dispersion characteristics of the prepared fluids were examined by UV/VIS spectroscopy at operating wavelengths ranging from 190 to 500 nm. Furthermore, the heat capacity and the electrical and thermal conductivity of the fluids were analyzed to evaluate their heat transfer performance and conductivity. The Lambda system was utilized for thermal conductivity measurement with operation at proper temperature ranges. The electrical conductivity of the fluids was measured by a conductivity meter. This experimental study revealed that the cellulose nanocrystal was an effective source of the noncovalent dispersion agent for thermal characteristics and was more eco-friendly than other surfactants. Moreover, cellulose aqueous solution can be used as a highly thermal efficient base fluid for nanofluid preparation.

Effect of Kenaf Fibre as Reinforcing Fillers in Corn Starch-Based Biocomposite Film

Biocomposite films were prepared using corn starch (CS), sorbitol as a plasticiser, and multi-scale kenaf fibre as reinforcing filler. The microstructure and the physical, tensile, and water barrier properties of corn starch reinforced with kenaf fibre were characterised and investigated. The biocomposite films were developed via the solution casting technique using 10 g of CS with 0 to 8% kenaf fibre as filler treated with 30% (w/w, starch basis) of sorbitol. The increased amount of kenaf fibre introduced contributed to improvements in film thickness, weight, and density. Conversely, slight reductions in the biocomposite films’ moisture content, water absorption, and solubility rating were 9.86–5.88%, 163.13–114.68%, and 38.98–25.17%, respectively. An X-ray diffraction (XRD) test revealed that the films were amorphous and that there was no effect on the crystallinity structure of films with kenaf fibre reinforcement. Fourier transform infrared (FT-IR) and rheological analysis indicated that kenaf fibre could weaken the molecular interaction of the film matrix. Field emission scanning electron microscope (FESEM) revealed the arrangement and uniform distribution of kenaf fibre at 0.2–0.8%. The incorporation of kenaf increased the tensile strength, Young’s modulus, and elongation at break until (6% wt) of fibre. With the kenaf fibre incorporation, the optimal tensile strength, Young’s modulus, and elongation at break of the films reached 17.74 MPa, 1324.74 MPa, and 48.79%, respectively. Overall, the introduction of kenaf fibre as filler enhanced the physical and mechanical properties of CS films.

Emerging Developments on Nanocellulose as Liquid Crystals: A Biomimetic Approach

Biomimetics is the field of obtaining ideas from nature that can be applied in science, engineering, and medicine. The usefulness of cellulose nanocrystals (CNC) and their excellent characteristics in biomimetic applications are exciting and promising areas of present and future research. CNCs are bio-based nanostructured material that can be isolated from several natural biomasses. The CNCs are one-dimensional with a high aspect ratio. They possess high crystalline order and high chirality when they are allowed to assemble in concentrated dispersions. Recent studies have demonstrated that CNCs possess remarkable optical and chemical properties that can be used to fabricate liquid crystals. Research is present in the early stage to develop CNC-based solvent-free liquid crystals that behave like both crystalline solids and liquids and exhibit the phenomenon of birefringence in anisotropic media. All these characteristics are beneficial for several biomimetic applications. Moreover, the films of CNC show the property of iridescent colors, making it suitable for photonic applications in various devices, such as electro-optical devices and flat panel displays.

Recycling of Waste Cotton Textile Containing Elastane Fibers through Dissolution and Regeneration

Increasing utilization of textiles has raised concern regarding the environmental impact brought by the textile manufacturing process and disposal of waste textiles. In our previous work, the dissolution of cotton waste through different solvent systems was demonstrated. Herein, this study aimed to further investigate the recycling of waste cotton–elastane fabrics using H₂SO₄, NaOH/urea, and LiCl/DMAc solvent systems. The structure of regenerated films was characterized with Fourier transform infrared spectroscopy and scanning electron microscopy, and the properties of the regenerated films, including transparency, mechanical properties, water vapor permeability, and thermal stability, were investigated. The results revealed that all solvent systems could convert the waste cotton–elastane fabrics into regenerated films with the existence of different forms of elastane components. The elastane fibers were partially hydrolyzed in H₂SO₄ solvent and reduced the transparency of regenerated films, but they were well retained in NaOH/urea solvent and interrupted the structure of regenerated cellulose films. It is worth noting that the elastane fibers were completely dissolved in LiCl/DMAc solvent and formed a composite structure with cellulose, leading to obviously improved tensile strength (from 51.00 to 121.63 MPa) and water barrier property (from 3.50 × 10⁻⁷ to 1.03 × 10⁻⁷ g m⁻¹ h⁻¹ Pa⁻¹). Therefore, this work demonstrates the possibility to directly recycle waste cotton–elastane fabrics through dissolution and regeneration, and the resultant films have potential applications as packaging materials.

Biochemistry, Synthesis, and Applications of Bacterial Cellulose: A Review

The potential of cellulose nanocomposites in the new-generation super-performing nanomaterials is huge, primarily in medical and environment sectors, and secondarily in food, paper, and cosmetic sectors. Despite substantial illumination on the molecular aspects of cellulose synthesis, various process features, namely, cellular export of the nascent polysaccharide chain and arrangement of cellulose fibrils into a quasi-crystalline configuration, remain obscure. To unleash its full potential, current knowledge on nanocellulose dispersion and disintegration of the fibrillar network and the organic/polymer chemistry needs expansion. Bacterial cellulose biosynthesis mechanism for scaled-up production, namely, the kinetics, pathogenicity, production cost, and product quality/consistency remain poorly understood. The bottom-up bacterial cellulose synthesis approach makes it an interesting area for still wider and promising high-end applications, primarily due to the nanosynthesis mechanism involved and the purity of the cellulose. This study attempts to identify the knowledge gap and potential wider applications of bacterial cellulose and bacterial nanocellulose. This review also highlights the manufacture of bacterial cellulose through low-cost substrates, that is, mainly waste from brewing, agriculture, food, and sugar industries as well as textile, lignocellulosic biorefineries, and pulp mills.

Sustainable Production of Stiff and Crystalline Bacterial Cellulose from Orange Peel Extract

In this work, a potentially economic and environmentally friendly method for the synthesis of bacterial cellulose (BC) by Gluconacetobacter xylinus from a biomass containing orange peel extract was evaluated. Orange peel extract was used as a culture medium without any hydrolysis treatment, thus speeding up the synthesis procedure. The efficacy of orange peel as a carbon source was compared with that of sucrose. The orange peel extract formed thicker cellulose gels than those formed using sucrose. X-ray diffraction (XRD) revealed both a high crystallinity index and crystallite size of BC nanofibers in samples obtained from orange peel (BC_Orange). Field emission scanning electron microscopy (FE-SEM) revealed a highly densely packed nanofibrous structure (50 nm in diameter). BC_Orange presented a two-fold increase in water holding capacity (WHC), and dynamic mechanical analysis (DMA) showed a 44% increase in storage modulus compared to sucrose derived BC. These results showed that the naturally available carbon sources derived from orange peel extract can be effectively used for BC production. The orange-based culture medium can be considered a profitable alternative to the generation of high-value products in a virtuous circular economy model.

Approaches for Extracting Nanofibrillated Cellulose from Oat Bran and Its Emulsion Capacity and Stability

The pretreatment process is an essential step for nanofibrillated cellulose production as it enhances size reduction efficiency, reduces production cost, and decreases energy consumption. In this study, nanofibrillated cellulose (NFC) was prepared using various pretreatment processes, either chemical (i.e., acid, basic, and bleach) or hydrothermal (i.e., microwave and autoclave), followed by disintegration using high pressure homogenization from oat bran fibers. The obtained NFC were used as an emulsifier to prepare 10% oil-in-water emulsions. The emulsion containing chemically pretreated NFC exhibited the smallest oil droplet diameter (d₃₂) at 3.76 μm, while those containing NFC using other pretreatments exhibited d₃₂ values > 5 μm. The colors of the emulsions were mainly influenced by oil droplet size rather than the color of the fiber itself. Both NFC suspensions and NFC emulsions showed a storage modulus (G′) higher than the loss modulus (G″) without crossing over, indicating gel-like behavior. For emulsion stability, microwave pretreatment effectively minimized gravitational separation, and the creaming indices of all NFC-emulsions were lower than 6% for the entire storage period. In conclusion, chemical pretreatment was an effective method for nanofiber extraction with good emulsion capacity. However, the microwave with bleaching pretreatment was an alternative method for extracting nanofibers and needs further study to improve the efficiency.

Natural Fiber-Reinforced Polycaprolactone Green and Hybrid Biocomposites for Various Advanced Applications

Recent developments within the topic of biomaterials has taken hold of researchers due to the mounting concern of current environmental pollution as well as scarcity resources. Amongst all compatible biomaterials, polycaprolactone (PCL) is deemed to be a great potential biomaterial, especially to the tissue engineering sector, due to its advantages, including its biocompatibility and low bioactivity exhibition. The commercialization of PCL is deemed as infant technology despite of all its advantages. This contributed to the disadvantages of PCL, including expensive, toxic, and complex. Therefore, the shift towards the utilization of PCL as an alternative biomaterial in the development of biocomposites has been exponentially increased in recent years. PCL-based biocomposites are unique and versatile technology equipped with several importance features. In addition, the understanding on the properties of PCL and its blend is vital as it is influenced by the application of biocomposites. The superior characteristics of PCL-based green and hybrid biocomposites has expanded their applications, such as in the biomedical field, as well as in tissue engineering and medical implants. Thus, this review is aimed to critically discuss the characteristics of PCL-based biocomposites, which cover each mechanical and thermal properties and their importance towards several applications. The emergence of nanomaterials as reinforcement agent in PCL-based biocomposites was also a tackled issue within this review. On the whole, recent developments of PCL as a potential biomaterial in recent applications is reviewed.

Isolation and characterization of cellulose nanofibers from Agave gigantea by chemical-mechanical treatment

Nanocellulose is a renewable and biocompatible nanomaterial that evokes much interest because of its versatility in various applications. This study reports the production of nanocellulose from Agave gigantea (AG) fiber using the chemical-ultrafine grinding treatment. Chemical treatment (alkalization and bleaching) removed non-cellulose components (hemicellulose and lignin), while ultrafine grinding reduced the size of cellulose microfibrils into nanocellulose. From the observation of Transmission Electron Microscopy, the average diameter of nanocellulose was 4.07 nm. The effect of chemical-ultrafine grinding on the morphology and properties of AG fiber was identified using chemical composition, Scanning Electron Microscopy, X-ray Diffraction, Fourier Transform Infrared, and Thermogravimetric Analysis. The bleaching treatment increased the crystal index by 48.3% compared to raw AG fiber, along with an increase in the cellulose content of 20.4%. The ultrafine grinding process caused a decrease in the crystal content of the AG fiber. The crystal index affected the thermal stability of the AG fiber. The TGA results showed that AG fiber treated with bleaching showed the highest thermal stability compared to AG fiber without treatment. The FTIR analysis showed that the presence of CH vibrations from the ether in the fiber. After chemical treatment, the peaks at 1605 and 1243 cm^-1 disappeared, indicating the loss of lignin and hemicellulose functional groups in AG fiber. As a result, nanocellulose derived from AG fiber can be applied as reinforcement in environmentally friendly polymer biocomposites.

Direct regeneration of hydrogels based on lemon peel and its isolated microcrystalline cellulose: Characterization and application for methylene blue adsorption

In this study, we developed a facile and eco-friendly fabrication of hydrogels based on lemon peel (LP) and its isolated microcrystalline cellulose (LPMCC) by direct co-dissolving in 1-butyl-3-methylimidazolium chloride (BmimCl), followed by direct regeneration in distilled water to form hydrogels. The influence of LP addition on the structure and methylene blue (MB) adsorption of the hydrogels was systematically investigated. The hydrogels displayed a physically cross-linked network through hydrogen bonding interactions. Compared with pure LPMCC hydrogel, the introduction of LP increased the porosity and improved the thermal stability of the hydrogels. The adsorption process of MB on the hydrogels conformed better to the pseudo-second-order kinetic (R² > 0.993) and Langmuir isotherm models (R² > 0.996). The MB adsorption process was feasible, spontaneous and exothermic in nature, and was influenced by initial MB concentration, pH, temperature, ionic type and strength. Notably, the introduction of LP improved MB adsorption capacity of the hydrogels. This work develops a facile approach of agricultural by-products based hydrogels using pure cellulose as the structural skeleton and untreated lignocellulose components as the structure modifier.

Modification of cellulose from sugarcane (Saccharum officinarum) bagasse pulp by cold plasma: Dissolution, structure and surface chemistry analysis

Cellulose is a most abundant natural biopolymer, however, the strong hydrogen bonding system makes cellulose hard to dissolve, limiting its further applications. In this study, an innovative cold plasma (CP) technology was used to modify cellulose from sugarcane (Saccharum officinarum) bagasse pulp. Dissolution, structure, and surface chemistry of cellulose before and after CP treatment were investigated. Results showed that the dissolution rate of cellulose after different CP treatment time (3-12 min) and operating voltage (40-70 kV) was significantly improved. Roughness, even holes (CP treatment 9 min with 50 kV) and breakage (CP treatment 9 min with 70 kV) were observed on the surface. The crystallinity index decreased from 62.31% (control) to 60.88% (CP treatment 3 min with 50 kV). The hydrogen bonding force was weakened and the peak intensity of CO and CO stretching vibration groups were enhanced. Therefore, CP-modified cellulose may be applied more in future, such as biological films for food future packaging.

Hybridization of MMT/Lignocellulosic Fiber Reinforced Polymer Nanocomposites for Structural Applications: A Review

In the recent past, significant research effort has been dedicated to examining the usage of nanomaterials hybridized with lignocellulosic fibers as reinforcement in the fabrication of polymer nanocomposites. The introduction of nanoparticles like montmorillonite (MMT) nanoclay was found to increase the strength, modulus of elasticity and stiffness of composites and provide thermal stability. The resulting composite materials has figured prominently in research and development efforts devoted to nanocomposites and are often used as strengthening agents, especially for structural applications. The distinct properties of MMT, namely its hydrophilicity, as well as high strength, high aspect ratio and high modulus, aids in the dispersion of this inorganic crystalline layer in water-soluble polymers. The ability of MMT nanoclay to intercalate into the interlayer space of monomers and polymers is used, followed by the exfoliation of filler particles into monolayers of nanoscale particles. The present review article intends to provide a general overview of the features of the structure, chemical composition, and properties of MMT nanoclay and lignocellulosic fibers. Some of the techniques used for obtaining polymer nanocomposites based on lignocellulosic fibers and MMT nanoclay are described: (i) conventional, (ii) intercalation, (iii) melt intercalation, and (iv) in situ polymerization methods. This review also comprehensively discusses the mechanical, thermal, and flame retardancy properties of MMT-based polymer nanocomposites. The valuable properties of MMT nanoclay and lignocellulose fibers allow us to expand the possibilities of using polymer nanocomposites in various advanced industrial applications.

Wheat Biocomposite Extraction, Structure, Properties and Characterization: A Review

Biocomposite materials create a huge opportunity for a healthy and safe environment by replacing artificial plastic and materials with natural ingredients in a variety of applications. Furniture, construction materials, insulation, and packaging, as well as medical devices, can all benefit from biocomposite materials. Wheat is one of the world’s most widely cultivated crops. Due to its mechanical and physical properties, wheat starch, gluten, and fiber are vital in the biopolymer industry. Glycerol as a plasticizer considerably increased the elongation and water vapor permeability of wheat films. Wheat fiber developed mechanical and thermal properties as a result of various matrices; wheat gluten is water insoluble, elastic, non-toxic, and biodegradable, making it useful in biocomposite materials. This study looked at the feasibility of using wheat plant components such as wheat, gluten, and fiber in the biocomposite material industry.

Physical, Mechanical, and Morphological Properties of Treated Sugar Palm/Glass Reinforced Poly(Lactic Acid) Hybrid Composites

This research was performed to evaluate the physical, mechanical, and morphological properties of treated sugar palm fiber (SPF)/glass fiber (GF) reinforced poly(lactic acid) (PLA) hybrid composites. Morphological investigations of tensile and flexural fractured samples of composites were conducted with the help of scanning electron microscopy (SEM). Alkaline and benzoyl chloride (BC) treatments of SPFs were performed. A constant weight fraction of 30% total fiber loading and 70% poly(lactic acid) were considered. The composites were initially prepared by a Brabender Plastograph, followed by a hot-pressing machine. The results reported that the best tensile and flexural strengths of 26.3 MPa and 27.3 MPa were recorded after alkaline treatment of SPF, while the highest values of tensile and flexural moduli of 607 MPa and 1847 MPa were recorded after BC treatment of SPF for SPF/GF/PLA hybrid composites. The novel SPF/GF/PLA hybrid composites could be suitable for fabricating automotive components.

Waste Natural Polymers as Potential Fillers for Biodegradable Latex-Based Composites: A Review

In recent years, biodegradable composites have become important in various fields because of the increasing awareness of the global environment. Waste natural polymers have received much attention as renewable, biodegradable, non-toxic and low-cost filler in polymer composites. In order to exploit the high potential for residual natural loading in latex composites, different types of surface modification techniques have been applied. This review discusses the preparation and characterization of the modified waste natural fillers for latex-based composites. The potency of the waste natural filler for the latex-based composites was explored with a focus on the mechanical, thermal, biodegradability and filler-latex interaction. This review also offers an update on the possible application of the waste natural filler towards the biodegradability of the latex-based composites for a more sustainable future.

Critical Review of Natural Fiber Reinforced Hybrid Composites: Processing, Properties, Applications and Cost

Increasing scientific interest has occurred concerning the utilization of natural fiber-enhanced hybrid composites that incorporate one or more types of natural enhancement. Annual natural fiber production is estimated to be 1,783,965 × 103 tons/year. Extensive studies have been conducted in the domains of natural/synthetic as well as natural/natural hybrid composites. As synthetic fibers have better rigidity and strength than natural fibers, natural/synthetic hybrid composites have superior qualities via hybridization compared to natural composites in fibers. In general, natural fiber compounds have lower characteristics, limiting the use of natural composites reinforced by fiber. Significant effort was spent in enhancing the mechanical characteristics of this group of materials to increase their strengths and applications, especially via the hybridization process, by manipulating the characteristics of fiber-reinforced composite materials. Current studies concentrate on enhancing the understanding of natural fiber-matrix adhesion, enhancing processing methods, and natural fiber compatibility. The optimal and resilient conceptions have also been addressed due to the inherently more significant variabilities. Moreover, much research has tackled natural fiber reinforced hybrid composite costs. In addition, this review article aims to offer a review of the variables that lead to the mechanical and structural failure of natural fiber reinforced polymer composites, as well as an overview of the details and costings of the composites.

Use of Industrial Wastes as Sustainable Nutrient Sources for Bacterial Cellulose (BC) Production: Mechanism, Advances, and Future Perspectives

A novel nanomaterial, bacterial cellulose (BC), has become noteworthy recently due to its better physicochemical properties and biodegradability, which are desirable for various applications. Since cost is a significant limitation in the production of cellulose, current efforts are focused on the use of industrial waste as a cost-effective substrate for the synthesis of BC or microbial cellulose. The utilization of industrial wastes and byproduct streams as fermentation media could improve the cost-competitiveness of BC production. This paper examines the feasibility of using typical wastes generated by industry sectors as sources of nutrients (carbon and nitrogen) for the commercial-scale production of BC. Numerous preliminary findings in the literature data have revealed the potential to yield a high concentration of BC from various industrial wastes. These findings indicated the need to optimize culture conditions, aiming for improved large-scale production of BC from waste streams.

Nanocrystalline Cellulose from Microcrystalline Cellulose of Date Palm Fibers as a Promising Candidate for Bio-Nanocomposites: Isolation and Characterization

Date palm fiber (Phoenix dactylifera L.) is a natural biopolymer rich in lignocellulosic components. Its high cellulose content lends them to the extraction of tiny particles like microcrystalline cellulose (MCC) and nanocrystalline cellulose (NCC). These cellulose-derived small size particles can be used as an alternative biomaterial in wide fields of application due to their renewability and sustainability. In the present work, NCC (A) and NCC (B) were isolated from date palm MCC at 60 min and 90 min hydrolysis times, respectively. The isolated NCC product was subjected to characterization to study their properties differences. With the hydrolysis treatment, the yields of produced NCC could be attained at between 22% and 25%. The infrared-ray functional analysis also revealed the isolated NCC possessed a highly exposed cellulose compartment with minimized lignoresidues of lignin and hemicellulose. From morphology evaluation, the nanoparticles’ size was decreased gradually from NCC (A) (7.51 nm width, 139.91 nm length) to NCC (B) (4.34 nm width, 111.51 nm length) as a result of fragmentation into cellulose fibrils. The crystallinity index was found increasing from NCC (A) to NCC (B). With 90 min hydrolysis time, NCC (B) showed the highest crystallinity index of 71% due to its great cellulose rigidity. For thermal analysis, NCC (B) also exhibited stable heat resistance, in associating with its highly crystalline cellulose structure. In conclusion, the NCC isolated from date palm MCC would be a promising biomaterial for various applications such as biomedical and food packaging applications.

Representative 2D-material-based nanocomposites and their emerging applications: a review

Composites (or complex materials) are formed from two or many constituent materials with novel physical or chemical characteristics when integrated. The individual components can be combined to create a unique composite material through mechanical transfer, physical stacking, exfoliation, derivative chemical mixtures, mixtures of solid solutions, or complex synthesis processes. The development of new composites based on emerging 2D nanomaterials has allowed for outstanding achievements with novel applications that were previously unknown. These new composite materials show massive potential in emerging applications due to their exceptional properties, such as being strong, light, cheap, and highly photodegradable, and their ability to be used for water splitting and energy storage compared to traditional materials. The blend of existing polymers and 2D materials with their nanocomposites has proven to be immediate solutions to energy and food scarcity in the world. Although much literature has been reported in the said context, we tried to provide an understanding about the relationship of their mechanisms and scope for future application in a comprehensive way. In this review, we briefly summarize the basic characteristics, novel physical and chemical behaviors, and new applications in the industry of the emerging 2D-material-based composites.

Composites (or complex materials) are formed from two or many constituent materials with novel physical or chemical characteristics when integrated.