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The growing concern about environmental pollution has generated an increased demand for biobased and biodegradable materials intended particularly for the packaging sector. Thus, this study focuses on the effect of two different cellulosic reinforcements and plasticized poly(3-hydroxybutyrate) (PHB) on the properties of poly(lactic acid) (PLA). The cellulose fibers containing lignin (CFw) were isolated from wood waste by mechanical treatment, while the ones without lignin (CF) were obtained from pure cellulose by acid hydrolysis. The biocomposites were prepared by means of a melt compounding-masterbatch technique for the better dispersion of additives. The effect of the presence or absence of lignin and of the size of the cellulosic fibers on the properties of PLA and PLA/PHB was emphasized by using in situ X-ray diffraction, polarized optical microscopy, atomic force microscopy, and mechanical and thermal analyses. An improvement of the mechanical properties of PLA and PLA/PHB was achieved in the presence of CF fibers due to their smaller size, while CFw fibers promoted an increased thermal stability of PLA/PHB, owing to the presence of lignin. The overall thermal and mechanical results show the great potential of using cheap cellulose fibers from wood waste to obtain PLA/PHB-based materials for packaging applications as an alternative to using fossil based materials. In addition, in situ X-ray diffraction analysis over a large temperature range has proven to be a useful technique to better understand changes in the crystal structure of complex biomaterials.

Bacterial cellulose (BC) is recognized as a multifaceted, versatile biomaterial with abundant applications. Groups of microorganisms such as bacteria are accountable for BC synthesis through static or agitated fermentation processes in the presence of competent media. In comparison to static cultivation, agitated cultivation provides the maximum yield of the BC. A pure cellulose BC can positively interact with hydrophilic or hydrophobic biopolymers while being used in the biomedical domain. From the last two decades, the reinforcement of biopolymer-based biocomposites and its applicability with BC have increased in the research field. The harmony of hydrophobic biopolymers can be reduced due to the high moisture content of BC in comparison to hydrophilic biopolymers. Mechanical properties are the important parameters not only in producing green composite but also in dealing with tissue engineering, medical implants, and biofilm. The wide requisition of BC in medical as well as industrial fields has warranted the scaling up of the production of BC with added economy. This review provides a detailed overview of the production and properties of BC and several parameters affecting the production of BC and its biocomposites, elucidating their antimicrobial and antibiofilm efficacy with an insight to highlight their therapeutic potential.

The study evaluated the preparation of a biocomposite using waste-derived polyhydroxybutyrate (PHB) and bagasse cellulose (α-cellulose) in a biorefinery approach. PHB was produced using dark fermentation effluent rich in volatile fatty acids (VFA) derived from vegetable waste and α-cellulose was extracted from sugarcane bagasse (SCB). Nutrient limitation induced microbial PHB accumulation, wherein maximum production of 0.28 ± 0.06 g PHB/g DCW (28%) was observed. Confocal examination showed the deposition of PHB granules in the cell cytoplasm and NMR spectrum exhibited a structural correlation. α-Cellulose (0.22 ± 0.02 g α-cellulose/g SCB) was extracted through SCB pretreatment. Thereafter, grafting α-cellulose with PHB offered intermolecular bonding, which resulted in enhanced thermal stability of the biocomposite than corresponding pristine PHB. FE-SEM morphological examination of biocomposite depicted that α-cellulose functioned as a filler to PHB. XRD profiles showed significant decrement in PHB crystallinity, signifying the functional role of α-cellulose as an effective reinforcing agent. Additionally, ether functional group of α-cellulose and ester group of PHB also appeared in XPS analysis of the composite, thus authorizing the effective blending of α-cellulose and PHB. Utilization of bagasse-derived cellulose for strengthening biologically produced PHB expands its applications, while simultaneously addressing the plastic pollution issues. Additional value from this process was further achieved by incorporating the concept of biorefinery, wherein acidogenic fermentation effluents were used for the production of PHA, which enabled the re-entry of products (VFA) to the production cycle, thus achieving circularity., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The degradation and mechanical properties of potential polymeric materials used for green manufacturing are significant determinants. In this study, cellulose nanofibre was prepared from Schizostachyum brachycladum bamboo and used as reinforcement in the PLA/chitosan matrix using melt extrusion and compression moulding method. The cellulose nanofibre(CNF) was isolated using supercritical carbon dioxide and high-pressure homogenisation. The isolated CNF was characterised with transmission electron microscopy (TEM), FT-IR, zeta potential and particle size analysis. The mechanical, physical, and degradation properties of the resulting biocomposite were studied with moisture content, density, thickness swelling, tensile, flexural, scanning electron microscopy, thermogravimetry, and biodegradability analysis. The TEM, FT-IR, and particle size results showed successful isolation of cellulose nanofibre using this method. The result showed that the physical, mechanical, and degradation properties of PLA/chitosan/CNF biocomposite were significantly enhanced with cellulose nanofibre. The density, thickness swelling, and moisture content increased with the addition of CNF. Also, tensile strength and modulus; flexural strength and modulus increased; while the elongation reduced. The carbon residue from the thermal degradation and the glass transition temperature of the PLA/chitosan/CNF biocomposite was observed to increase with the addition of CNF. The result showed that the biocomposite has potential for green and sustainable industrial application.

Biocomposites of copper-containing mesoporous bioactive glass (Cu-MBG) and nanofibrillated cellulose (NFC) were designated as potential dressing material for chronic wound healing. The phase composition and mesoporous micro-structure of the synthesized Cu-MBGs were elaborately characterized by combining several techniques, including TEM, SEM, XRD, SXAS and N 2 physisorption. High bioactivity of the Cu-MBG was confirmed in stimulated body fluids in vitro. A controlled dissolution of Cu from the glass suggests Cu-MBG a suitable source for Cu release in wound healing dressings. Depending on the content of Cu-MBG in the composite formulation, the composites were fabricated as membranes and aerogels. In biocompatibility assessment of the composites, a dose-dependent cytotoxicity of Cu 2+ on 3T3 fibroblasts was found. Importantly, a critical biological level of Cu 2+ below 10mg/L was suggested for the survival and growth of 3T3 fibroblasts. The Cu 2+ released from the composite aerogel of NFC and Cu-MBG showed a profound angiogenic effect in the 3D spheroid culture system of human umbilical vein endothelial cells. Moreover, the angiogenic gene expression of 3T3 fibroblast was upregulated in the real-time quantitative PCR analysis, which also confirms that the incorporation of Cu-MBG into NFC matrix enhances the proangiogenic potential of the biocomposites. In addition, composites of NFC and Cu-MBG also showed an inhibiting effect on the growth of E. coli., Statement of Significance: To address an urgent need in clinics on developing a new generation of therapeutic dressings with advanced functionalities, this study has exploited the utilization of Cu-containing mesoporous bioactive glass in the nanocellulose matrix to release Cu 2+ as therapeutic ions for its angiogenic effect on promoting wound healing. This manuscript reports research work on biomaterial design, fabrication development, material characterizations and bioassessments in 2D cellular studies. To utilize nanocellulose derived from the wood resource in biomedical applications is of great significance, due to its vast availability and bioeconomy competence. The use of Cu-containing bioactive glass in tissue engineering scaffolds, including wound healing, is an intriguing research topic, which has been recently discussed in the field of biomaterials. I think that our manuscript title with 'Biocomposites of copper-containing mesoporous bioactive glass and nanofibrillated cellulose: biocompatibility and angiogenic promotion in chronic wound healing application' will make its own contribution on understanding the complex effects of Cu 2+ on wound-healing-relevant events with acceptable novelty for Acta Biomaterialia., (Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

In this study, the integration of paper industry waste with high cellulose content into biocomposites of polylactic acid (PLA), a widely used biobased polymer material, was investigated. The PLA/waste biocomposite samples (0–25 wt.%) were manufactured using the extrusion and injection moulding techniques. The mechanical test results showed improvements in terms of tensile properties and a decrease in impact strength as the percentage of residue increased. The melting temperature decreased, and the crystallinity increased in all biocomposites according to the Differential Scanning Calorimetry (DSC) analysis. Water absorption increased proportionally with the percentage of residue, attributed to the higher cellulose content in the biocomposites, determined by Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) techniques. The scanning electron microscopy (SEM) fracture analysis demonstrated effective reinforcement–matrix cohesion, supporting the previously observed behaviour of the analysed materials. This work highlights the potential of using waste from the paper industry as reinforcement in PLA matrices, opening new perspectives for sustainable applications in the framework of the manufacture of composite materials. [ABSTRACT FROM AUTHOR]

Biopolymers are biodegradable and renewable and can significantly reduce environmental impacts. For this reason, biocomposites based on a plasticized starch and cross-linker matrix and with a microfibrillated OCC cardboard cellulose reinforcement were developed. Biocomposites were prepared by suspension casting with varied amounts of microfibrillated cellulose: 0, 4, 8, and 12 wt%. Polyethylene glycol diglycidyl ether (PEGDE) was used as a cross-linking, water-soluble, and non-toxic agent. Microfibrillated cellulose (MFC) from OCC cardboard showed appropriate properties and potential for good performance as a reinforcement. In general, microfiber incorporation and matrix cross-linking increased crystallization, reduced water adsorption, and improved the physical and tensile properties of the plasticized starch. Biocomposites cross-linked with PEGDE and reinforced with 12 wt% MFC showed the best properties. The chemical and structural changes induced by the cross-linking of starch chains and MFC reinforcement were confirmed by FTIR, NMR, and XRD. Biodegradation higher than 80% was achieved for most biocomposites in 15 days of laboratory compost. [ABSTRACT FROM AUTHOR]

In this study, the integration of paper industry waste with high cellulose content into biocomposites of polylactic acid (PLA), a widely used biobased polymer material, was investigated. The PLA/waste biocomposite samples (0–25 wt.%) were manufactured using the extrusion and injection moulding techniques. The mechanical test results showed improvements in terms of tensile properties and a decrease in impact strength as the percentage of residue increased. The melting temperature decreased, and the crystallinity increased in all biocomposites according to the Differential Scanning Calorimetry (DSC) analysis. Water absorption increased proportionally with the percentage of residue, attributed to the higher cellulose content in the biocomposites, determined by Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) techniques. The scanning electron microscopy (SEM) fracture analysis demonstrated effective reinforcement–matrix cohesion, supporting the previously observed behaviour of the analysed materials. This work highlights the potential of using waste from the paper industry as reinforcement in PLA matrices, opening new perspectives for sustainable applications in the framework of the manufacture of composite materials.

The effect of the chemical treatment of paper mill sludge fibers and polypropylene molecular weight were studied relative to the physical, mechanical, and morphological properties of a novel cellulosic biocomposite. Paper mill sludge fibers were treated with acetic anhydride, and succinic anhydride was mixed with maleic anhydride polypropylene (MAPP) and coupling agent (0 and 3%). The ratio of fibers and polymer materials was considered 30 to 70, which was manufactured by the hot-pressing method at 180 °C. Water absorption, volume swelling, and contact angle were examined on each specimen according to ASTM standards, while Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) explored the efficiency of chemical modification of fibers and the morphology of biocomposites, respectively. The results showed that chemical treatment of fibers reduced the water absorption and volumetric swelling. Both tensile and flexural strength were increased with chemical treatment using the coupling agent. Comparison of fibers treated with succinic acid and acetic acid showed that the succinic acid enhanced the mechanical properties better than the acetic acid treatment. Finally, FTIR analysis showed that the hydroxyl groups decreased, and SEM images indicated the interface between fibers and polypropylene improved via chemical treatment of sludge fibers.

The effect of the chemical treatment of paper mill sludge fibers and polypropylene molecular weight were studied relative to the physical, mechanical, and morphological properties of a novel cellulosic biocomposite. Paper mill sludge fibers were treated with acetic anhydride, and succinic anhydride was mixed with maleic anhydride polypropylene (MAPP) and coupling agent (0 and 3%). The ratio of fibers and polymer materials was considered 30 to 70, which was manufactured by the hotpressing method at 180 °C. Water absorption, volume swelling, and contact angle were examined on each specimen according to ASTM standards, while Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) explored the efficiency of chemical modification of fibers and the morphology of biocomposites, respectively. The results showed that chemical treatment of fibers reduced the water absorption and volumetric swelling. Both tensile and flexural strength were increased with chemical treatment using the coupling agent. Comparison of fibers treated with succinic acid and acetic acid showed that the succinic acid enhanced the mechanical properties better than the acetic acid treatment. Finally, FTIR analysis showed that the hydroxyl groups decreased, and SEM images indicated the interface between fibers and polypropylene improved via chemical treatment of sludge fibers. [ABSTRACT FROM AUTHOR]

Cellulose-Sn(IV) (CSn) biocomposite was synthesized by cellulose and stannic chloride in ethanol medium using microwave irradiation for 2 min with 30 s of intermittent time intervals. The incorporation of Sn(IV) into the cellulose matrix was confirmed through FT-IR, XRD, TGA, SEM- EDS, and BET. The prepared composite CSn has been used for the adsorptive removal of As(III) from water. Parameters, such as initial concentration, adsorbent dose, initial As(III) concentration, and time required for the adsorption process, were optimized through the batch-adsorption process. The adsorption capacity of the CSn for As(III) adsorption was found to be 16.64 mg/g at pH 7.0. Freundlich isotherm was found to be more suitable for the adsorption process based on regression coefficient values. Pseudo-second-order kinetic model was found to be more suitable for understanding the kinetics of the adsorption of As(III). Weber–Morris model with non-zero intercept revealed that the mechanism of adsorption was not limited to the diffusion process only. The adsorption process was spontaneous and exothermic and showed a decrease in randomness. Chloride ions decreased the percentage removal of As(III) when the concentration of chloride ions was ten times that of As(III) concentration according to the results obtained through the effect of co-anions study. In this study, 5% (w/v) NaCl solution has been used for the regeneration of the material, and during up to five adsorption–desorption cycles, there was a gradual decrease in percentage removal of As(III) from 95% to 78% only, which proves the greener aspect of the CSn. The breakthrough volume of 1.25 L of 10 mg/L of As(III) in column studies revealed that the CSn could be applicable for larger sample volumes also. [ABSTRACT FROM AUTHOR]

The aim of this study was to obtain biocomposites consisting of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), bacterial cellulose (BC) and α-tocopherol by a melt processing technique for potential use in biomedical applications. The melt processing and roughness of biocomposites were evaluated and compared to sample without BC. The degradation rate of PHBV/BC biocomposites was measured in phosphate buffer saline (PBS) by determining the mass variation and evidencing of thermal and structural changes by differential scanning calorimetry (DSC) and attenuated total reflectance-Fourier transformed infrared spectrometry (ATR-FTIR). The cell viability, cell morphology, cell cycle distribution and total collagen content were investigated on murine NCTC fibroblasts. Overall, the adding of BC to polyester matrix led to an adequate melt processing of biocomposites and increased surface roughness and cytocompatibility, allowing the cells to secrete the extracellular matrix (collagen) and stimulate cell proliferation. Results showed that the PHBV/BC biocomposites were favorable for long-term degradation and could be used for the design of medical devices with controlled degradability. [ABSTRACT FROM AUTHOR]

The emerging concepts of sustainable textiles and controlled production strategy demands ideally zero emissions of contaminants into the aquatic environment. However, the currently in-practiced conventional processes in textiles dispose of a number of contaminants especially super toxic synthetic dyes as effluents. In recent years, nanomaterials have become attractive choice for eco-friendly removal of organic dyestuff. Accordingly, this article reports synthesis and characterization of biocomposite wherein copolymer of polyaniline (PANI) and Polypyrrole (PPY) was grafted onto hydroxyethyl cellulose (HEC). Further, adsorption properties of as-prepared composite were evaluated using textile dyes Rhodamine B (RhB) and methyl Orange (MO)- as model adsorbate. The characterization of novel biocomposite (HEC/PANI-PPy) was carried out using Fourier Transform Infrared (FT-IR), Brunauer-Emmett-Teller analyzer (BET), Scanning Electron Microscope (SEM), and powder X-ray diffraction (XRD). The operational parameters such as dye initial concentration, adsorbent amount, pH and contact time were also studied to evaluate the efficiency level of the prepared biocomposite. Interestingly, the composite-mediated adsorption of RhB and MO followed pseudo-second order and the Langmuir isotherm. It is found that the adsorption capacity HEC/PANI-PPy is 30.06 and 29.3 for RhB and MO respectively. Thus, HEC/PANI-PPy is an inexpensive and highly efficient adsorbent that could be employed for could be employed for the separation and removal of toxic organic dyes from polluted textile effluents. [ABSTRACT FROM AUTHOR]

This work investigates the rheological behavior and characteristics of solutions and convened biopolymer films from Chitosan (Chi) modified by kombucha-derived bacterial cellulose (KBC). The Arrhenius equation and the Ostwald de Waele model (power-law) revealed that the Chi/KBC solutions exhibited non-Newtonian behavior. Both temperature and KBC concentration strongly affected their solution viscosity. With the selection of a proper solvent for chitosan solubilization, it may be possible to improve the performances of chitosan films for specific applications. The elasticity of the prepared films containing KBC 10% w/w was preferable when compared to the controls. FTIR analysis has confirmed the presence of bacterial cellulose, chitosan acetate, and chitosan lactate as the corresponding components in the produced biopolymer films. The thermal behaviors of the Chi (lactic acid)/KBC samples showed slightly higher stability than Chi (acetic acid)/KBC. Generally, these results will be helpful in the preparation processes of the solutions and biopolymer films of Chi dissolved in acetic or lactic acid modified by KBC powder to fabricate food packaging, scaffolds, and bioprinting inks, or products related to injection or direct extrusion through a needle. [ABSTRACT FROM AUTHOR]

Cellulose-Sn(IV) (CSn) biocomposite was synthesized by cellulose and stannic chloride in ethanol medium using microwave irradiation for 2 min with 30 s of intermittent time intervals. The incorporation of Sn(IV) into the cellulose matrix was confirmed through FT-IR, XRD, TGA, SEM- EDS, and BET. The prepared composite CSn has been used for the adsorptive removal of As(III) from water. Parameters, such as initial concentration, adsorbent dose, initial As(III) concentration, and time required for the adsorption process, were optimized through the batch-adsorption process. The adsorption capacity of the CSn for As(III) adsorption was found to be 16.64 mg/g at pH 7.0. Freundlich isotherm was found to be more suitable for the adsorption process based on regression coefficient values. Pseudo-second-order kinetic model was found to be more suitable for understanding the kinetics of the adsorption of As(III). Weber–Morris model with non-zero intercept revealed that the mechanism of adsorption was not limited to the diffusion process only. The adsorption process was spontaneous and exothermic and showed a decrease in randomness. Chloride ions decreased the percentage removal of As(III) when the concentration of chloride ions was ten times that of As(III) concentration according to the results obtained through the effect of co-anions study. In this study, 5% (w/v) NaCl solution has been used for the regeneration of the material, and during up to five adsorption–desorption cycles, there was a gradual decrease in percentage removal of As(III) from 95% to 78% only, which proves the greener aspect of the CSn. The breakthrough volume of 1.25 L of 10 mg/L of As(III) in column studies revealed that the CSn could be applicable for larger sample volumes also.

Polyethylene-cellulose biocomposites were synthesized here via the ethylene polymerization with metallocene as a catalyst along with methylaluminoxane (MAO) as a cocatalyst. The immobilization method in which the catalyst or cocatalyst is fixed onto the catalytic filler (cellulose) can be classified into 3 methods according to the active components fixed onto the filler surface: 1) only metallocene catalyst (Cellulose/Zr), 2) only MAO cocatalyst (Cellulose/MAO) and 3) mixture of metallocene and MAO (Cellulose/(Zr+MAO)). It was found that the different immobilization methods or different fillers altered the properties of the obtained composites and also the catalytic activity of the polymerization systems. It was found that Cellulose/MAO provided the highest catalytic activity among all fillers due to a crown-alumoxane complex, which caused the heterogeneous system with this filler behaved similarly to the homogeneous system. The different fillers also produced the biocomposites with some different properties such as crystallinity which Cellulose/Zr provided the highest crystallinity compared with other fillers as observed by a thermal gravimetric analysis-differential scanning calorimetry (TGA-DSC). Nevertheless, the main crystal structure indicated to the typical polyethylene was still observed for all obtained biocomposites with different fillers as observed by an X-ray diffractometer (XRD). Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Simple and cost-effective, eco-friendly, graphene-based “green” nanocomposite films are produced with the solvent casting method. For this purpose, commercially procured nanographene was used as reinforcement material and 2-hydroxyethyl cellulose (2-HEC), a cellulose-derivative natural polymer, was used as a matrix. Nanographene was modified with HCl and HNO3 to ensure blending with the cellulose matrix, and 2-HEC/acid modified graphene nanocomposite films were produced. The results show that the basic structure of the graphene is preserved after the HCl and HNO3 modifications. FT-IR, XRD, and Raman Spectroscopy results show that the graphene attained hydrophilic property by creating functional ends (hydroxyl group, –OH) on the edges of the graphene sheet with acid modification. Morphology studies with SEM and AFM methods have also confirmed the acid modification to the graphene. TGA/DTG work revealed that nanocomposite films obtained as a result of the doping of HNO3 modified graphene to the 2-HEC matrix were found to be thermally more stable than the original 2-HEC film. In this study, where 2-HEC is used as a matrix, the hydrophilic property has been achieved with the hydrophobic graphene by acid modification. The resulting 2-HEC/acid modified graphene nanocomposite materials have the potential to lead to innovation in applications such as lithium-ion batteries and sensor design, water treatment and even drug delivery systems.

Dressing biomaterials play a key role in wound management keeping a moisture medium and protecting against external factors. Natural and synthetic materials could be used as dressings where chitosan and bacterial cellulose is one of the most important solutions. These biopolymers have been used for wound dressing based on their non-toxic, biodegradable, and biocompatible features. In this study, biocomposites based on bacterial cellulose and chitosan membranes tailored with antimicrobial loaded poly(N-isopropylacrylamide)/polyvinyl alcohol nanoparticles were prepared. Core-shell polymeric nanoparticles, bacterial cellulose/chitosan membranes, and biocomposites were independently loaded with silver sulfadiazine, a well-known sulfonamide antibacterial agent used in the therapy of mild-to-moderate infections for sensitive organisms. The chemistry, structure, morphology, and size distribution were investigated by Fourier transformed infrared spectroscopy (FTIR-ATR), RAMAN spectroscopy, Scanning electron (SEM) and Transmission electron microscopy (TEM), and Dynamic light scattering (DLS). In vitro release behaviors of silver sulfadiazine from polymeric nanoparticles and biocomposites were investigated. The biological investigations revealed good biocompatibility of both the nanoparticles and the biocomposites in terms of human dermal fibroblasts viability and proliferation potential. Finally, the drug-loaded polymeric biomaterials showed promising characteristics, proving their high potential as an alternative support to develop a biocompatible and antibacterial wound dressing. [ABSTRACT FROM AUTHOR]

Climate change, waste disposal challenges, and emissions generated by the manufacture of non-renewable materials are driving forces behind the production of more sustainable composite materials. All-cellulose composites (ACCs) originate from renewable biomass, such as trees and other plants, and are considered fully biodegradable. Dissolving cellulose is a common part of manufacturing ACCs, and currently there is a lot of research focused on effective, but also more environmentally friendly cellulose solvents. There are several beneficial properties of ACC materials that make them competitive: light weight, recyclability, low toxicity, good optical, mechanical, and gas barrier properties, and abundance of renewable plant-based raw material. The most prominent ACC applications are currently found in the food packing, medical, technical and vehicle industries. All-cellulose nanocomposites (ACNCs) expand the current research field and can offer a variety of more specific and functional applications. This review provides an overview of the manufacture of sustainable ACCs from lignocellulose, purified cellulose, and cellulosic textiles. There is an introduction of the cellulose dissolution practices of creating ACCs that are currently researched, the structure of cellulose during complete or partial dissolution is discussed, and a brief overview of factors which influence composite properties is presented. [ABSTRACT FROM AUTHOR]

Several studies report the potential of bacterial cellulose (BC) in the fashion and leather industries. This work aimed at the development of BC-based composites containing emulsified acrylated epoxidized soybean oil (AESO) that are polymerized with the redox initiator system hydrogen peroxide (H2O2) and L-ascorbic acid and ferrous sulfate as a catalyst. BC was fermented under static culture. The polymerization of the emulsified organic droplets was tested before and after their incorporation into BC by exhaustion. The composites were then finished with an antimicrobial agent (benzalkonium chloride) and dyed. The obtained composites were characterized in terms of wettability, water vapor permeability (WVP), mechanical, thermal and antimicrobial properties. When AESO emulsion was polymerized prior to the exhaustion process, the obtained composites showed higher WVP, tensile strength and thermal stability. Meanwhile, post-exhaustion polymerized AESO conferred the composite higher hydrophobicity and elongation. The composites finished with the antimicrobial agent showed activity against S. aureus. Finally, intense colors were obtained more uniformly when they were incorporated simultaneously with the emulsified AESO with all the dyes tested. [ABSTRACT FROM AUTHOR]

Adding acid-modified resin compatibilizers is essential for plastic composites reinforced with carbon-neutral cellulosic filler. Researchers have measured the efficacy of adding a compatibilizer in the context of mechanics. However, it is necessary to microscopically clarify how the compatibilizer actually works for quality control and further expansion of applications. In this review, the author first describes the situation of cellulosic composites and presents issues regarding how one assesses the role of the compatibilizer. The author then reviews recent multi-scale experimental approaches to the detection of covalent bonds between the cellulosic filler and compatibilizer, estimation of nanoscale interphases, and the micron-scale dispersibility of the fillers. With accumulation of such experimental facts, appropriate parameter settings can be expected for the structural analysis such as the finite-element method, as well as the potential to provide appropriate explanatory variables for material/process informatics. [ABSTRACT FROM AUTHOR]

Carbon fiber reinforced composites have exceptional potential to play a key role in the materials world of our future. However, their success undoubtedly depends on the extent they can contribute to advance a global sustainability objective. Utilizing polymers in these composites that can be potentially derived from biomasses would be certainly vital for next-generation manufacturing practices. Nevertheless, deep understanding and tailoring fiber-matrix interactions are crucial issues in order to design carbon fiber reinforced sustainable resource-based biocomposites. In this study, cellulose derivatives (cellulose propionate and cellulose acetate butyrate) are utilized as model polymer matrices that can be potentially fabricated from biomasses, and the mechanical properties of the prepared short carbon fiber reinforced composites are engineered by means of a functional biobased lignin coating on the fiber surface. Furthermore, polyamide 6 based composites are also prepared, the monomer of this polymer could be obtained using C6 sugars derived from lignocellulosic biomasses in the future (through 5-hydroxymethylfurfural). Lignin was successfully immobilized on the carbon fiber surface via an industrially scalable benign epoxidation reaction. The surface modification had a beneficial impact on the mechanical properties of cellulose propionate and polyamide 6 composites. Furthermore, our results also revealed that cellulose-based matrices are highly sensitive to the presence of rigid fiber segments that restrict polymer chain movements and facilitate stress development. It follows that the physicochemical properties of the cellulosic matrices (molecular weight, crystallinity), associated with polymer chain mobility, might need to be carefully considered when designing these composites. At the same time, polyamide 6 showed excellent ability to accommodate short carbon fibers without leading to a largely brittle material, in this case, a maximum tensile strength of ~136 MPa was obtained at 20 wt% fiber loading. These results were further contrasted with that of a petroleum-based polypropylene matrix exhibiting inferior mechanical properties. Our study clearly indicates that carbon fiber reinforced polymers derived and designed using biomass-derived resources can be promising green materials for a sustainable future.

Climate change, waste disposal challenges, and emissions generated by the manufacture of non-renewable materials are driving forces behind the production of more sustainable composite materials. All-cellulose composites (ACCs) originate from renewable biomass, such as trees and other plants, and are considered fully biodegradable. Dissolving cellulose is a common part of manufacturing ACCs, and currently there is a lot of research focused on effective, but also more environmentally friendly cellulose solvents. There are several beneficial properties of ACC materials that make them competitive: light weight, recyclability, low toxicity, good optical, mechanical, and gas barrier properties, and abundance of renewable plant-based raw material. The most prominent ACC applications are currently found in the food packing, medical, technical and vehicle industries. All-cellulose nanocomposites (ACNCs) expand the current research field and can offer a variety of more specific and functional applications. This review provides an overview of the manufacture of sustainable ACCs from lignocellulose, purified cellulose, and cellulosic textiles. There is an introduction of the cellulose dissolution practices of creating ACCs that are currently researched, the structure of cellulose during complete or partial dissolution is discussed, and a brief overview of factors which influence composite properties is presented.

Polyethylene-cellulose biocomposites were synthesized here via the ethylene polymerization with metallocene as a catalyst along with methylaluminoxane (MAO) as a cocatalyst. The immobilization method in which the catalyst or cocatalyst is fixed onto the catalytic filler (cellulose) can be classified into 3 methods according to the active components fixed onto the filler surface: 1) only metallocene catalyst (Cellulose/Zr), 2) only MAO cocatalyst (Cellulose/MAO) and 3) mixture of metallocene and MAO (Cellulose/(Zr+MAO)). It was found that the different immobilization methods or different fillers altered the properties of the obtained composites and also the catalytic activity of the polymerization systems. It was found that Cellulose/MAO provided the highest catalytic activity among all fillers due to a crown-alumoxane complex, which caused the heterogeneous system with this filler behaved similarly to the homogeneous system. The different fillers also produced the biocomposites with some different properties such as crystallinity which Cellulose/Zr provided the highest crystallinity compared with other fillers as observed by a thermal gravimetric analysis-differential scanning calorimetry (TGADSC). Nevertheless, the main crystal structure indicated to the typical polyethylene was still observed for all obtained biocomposites with different fillers as observed by an X-ray diffractometer (XRD). [ABSTRACT FROM AUTHOR]

Composite materials comprising a mixture of shellac resin as the matrix and cellulose as the reinforcement were developed. The influence of the reinforcement content and the concentration of additives on the mechanical performance and processing were investigated. A high content of cellulose and low concentrations of ethanol and polyethylene glycol produced biocomposites with high stress resistance and a high Young’s modulus, whereas a low content of cellulose and a high concentration of additives gave samples a low Young’s modulus and high elasticity. Two types of cellulose-based reinforcements with different polarity, namely, mechanically refined wood pulp and cellulose acetate butyrate particles, were compared. The efficiency of the composite over the two model reinforcements, i.e., hydrophilic and hydrophobic components, respectively, was also studied. Although particle reinforcement was easier to process and evenly dispersed into the matrix, its mechanical performance was lower compared with refined fibres. Scanning electron microscopy showed that the matrix better coated the fibres than the particles, resulting in better adhesion and mechanical performance. The morphology of reinforcement played a key role; long fibres oriented in the pulling direction ensured a better mechanical resistance than particle fillers.

Fiber–matrix interfacial adhesion is one of the key factors governing the final properties of natural fiber-based polymer composites. In this work, four extrusion reactive agents were tested as potential compatibilizers in polyhydroxylbutyrate (PHB)/cellulose composites: dicumyl peroxide (DCP), hexamethylene diisocyanate (HMDI), resorcinol diglycidyl ether (RDGE), and triglycidyl isocyanurate (TGIC). The influence of the fibers and the different reactive agents on the mechanical properties, physical aging, and crystallization behavior were assessed. To evaluate the compatibilization effectiveness of each reactive agent, highly purified commercial cellulose fibers (TC90) were used as reference filler. Then, the influence of fiber purity on the compatibilization effect of the reactive agent HMDI was evaluated using untreated (U_RH) and chemically purified (T_RH) rice husk fibers, comparing the results with the ones using TC90 fibers. The results show that reactive agents interact with the polymer matrix at different levels, but all compositions showed a drastic embrittlement due to the aging of PHB. No clear compatibilization effect was found using DCP, RDGE, or TGIC reactive agents. On the other hand, the fiber–polymer interfacial adhesion was enhanced with HMDI. The purity of the fiber played an important role in the effectiveness of HMDI as a compatibilizer, since composites with highly purified fibers showed the greatest improvements in tensile strength and the most favorable morphology. None of the reactive agents negatively affected the compostability of PHB. Finally, thermoformed trays with good mold reproducibility were successfully obtained for PHB/T_RH/HMDI composition.

The potential of triticale straw for the production of green composites based on polypropylene (PP) was evaluated. The composites were prepared by melt compounding of PP and chopped triticale straw (so-called triticale particles) using different formulations and triticale concentrations. The morphology and crystallization of the PP triticale composites were characterized by means of various techniques, including optical microscopy (OM), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). The composite mechanical performance was also evaluated. The results obtained demonstrate that, by simply adding triticale particles into PP, they play the role of a conventional filler that increases the modulus while reduces the strength. However, the developed formulation with the combination of coupling agent and reactive additive provides superior strength and modulus for the composites; thus, it can upgrade the triticale particles from filler to reinforcement category.

Nanostructured materials are difficult to prepare rapidly and at large scale. Melt-processed polymer-clay nanocomposites are an exception, but the clay content is typically below 5 wt%. An approach for manufacturing of microfibrillated cellulose (MFC)/kaolinite nanocomposites is here demonstrated in pilot-scale by continuous production of hybrid nanopaper structures with thickness of around 100 μm. The colloidal nature of MFC suspensions disintegrated from chemical wood fiber pulp offers the possibility to add kaolinite clay platelet particles of nanoscale thickness. For initial lab scale optimization purposes, nanocomposite processing (dewatering, small particle retention etc) and characterization (mechanical properties, density etc) were investigated using a sheet former (Rapid Köthen). This was followed by a continuous fabrication of composite paper structures using a pilot-scale web former. Nanocomposite morphology was assessed by scanning electron microscopy (SEM). Mechanical properties were measured in uniaxial tension. The fire retardancy was evaluated by cone calorimetry. Inorganic hybrid composites with high content of in-plane oriented nanocellulose, nanoclay and wood fibers were successfully produced at pilot scale. Potential applications include fire retardant paperboard for semi structural applications and as reinforcement mats in molded thermoset biocomposites. [ABSTRACT FROM AUTHOR]

Materials that are both biodegradable and bio-sourced are becoming serious candidates for substituting traditional petro-sourced plastics that accumulate in natural systems. New biocomposites have been produced by melt extrusion, using bacterial polyester (poly(3-hydroxybutyrate-co-3-hydroxyvalerate)) as a matrix and cellulose particles as fillers. In this study, gas-phase esterified cellulose particles, with palmitoyl chloride, were used to improve filler-matrix compatibility and reduce moisture sensitivity. Structural analysis demonstrated that intrinsic properties of the polymer matrix (crystallinity, and molecular weight) were not more significantly affected by the incorporation of cellulose, either virgin or grafted. Only a little decrease in matrix thermal stability was noticed, this being limited by cellulose grafting. Gas-phase esterification of cellulose improved the filler’s dispersion state and filler/matrix interfacial adhesion, as shown by SEM cross-section observations, and limiting the degradation of tensile properties (stress and strain at break). Water vapor permeability, moisture, and liquid water uptake of biocomposites were increased compared to the neat matrix. The increase in thermodynamic parameters was limited in the case of grafted cellulose, principally ascribed to their increased hydrophobicity. However, no significant effect of grafting was noticed regarding diffusion parameters.

Composite materials comprising a mixture of shellac resin as the matrix and cellulose as the reinforcement were developed. The influence of the reinforcement content and the concentration of additives on the mechanical performance and processing were investigated. A high content of cellulose and low concentrations of ethanol and polyethylene glycol produced biocomposites with high stress resistance and a high Young's modulus, whereas a low content of cellulose and a high concentration of additives gave samples a low Young's modulus and high elasticity. Two types of cellulose-based reinforcements with different polarity, namely, mechanically refined wood pulp and cellulose acetate butyrate particles, were compared. The efficiency of the composite over the two model reinforcements, i.e., hydrophilic and hydrophobic components, respectively, was also studied. Although particle reinforcement was easier to process and evenly dispersed into the matrix, its mechanical performance was lower compared with refined fibres. Scanning electron microscopy showed that the matrix better coated the fibres than the particles, resulting in better adhesion and mechanical performance. The morphology of reinforcement played a key role; long fibres oriented in the pulling direction ensured a better mechanical resistance than particle fillers. [ABSTRACT FROM AUTHOR]