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Wood–plastic composites (WPCs) represent composite materials that employ shredded wood combined with a thermoplastic substance, such as polylactic acid (PLA), to establish structural cohesion within the product profile. This amalgamation of materials results in a robust structure designed to fulfill specialized roles under the influence of pressure and temperature. Given the nature of the constituent materials, the resultant product can be classified as a biocomposite. The creation of such biocomposites entails a rigorous process necessitating the fine-tuning of specific parameters and suitable technologies. The foundational materials employed in this process must be both natural and biodegradable. However, it is noteworthy that natural components like fibers exhibit anisotropic behavior, wherein their mechanical attributes are contingent on the direction of the applied force. Consequently, predicting their performance during biocomposite production proves challenging. The principal objective of this study was to conduct a comparative analysis of wood-based composites incorporating PLA thermoplastic binding agents. The intention was to discern variations in density profiles arising from distinct measurement methodologies. Two measurement methods were used for the measurement: X-ray and spectrum desaturation. Additionally, the study sought to investigate the impact of introducing PLA additives at 25% and 50% concentrations on the fabrication of WPC from wood chips. The properties of these composites were assessed by considering the inherent traits of the composite materials. [ABSTRACT FROM AUTHOR]

The eco-design considers the factors to prepare biocomposites under an end-of-life scenario. PLA/sisal biocomposites were obtained from amorphous polylactide and sisal loadings of 10, 20 and 30 wt% with and without coupling agent, and subjected to biodegradation in soil according to standard ISO846. Mass-loss, differential scanning calorimetry and size-exclusion chromatography were used for monitoring biodegradation. A statistical factorial analysis based on the molar mass M n and crystallinity degree X C pointed out the relevance and interaction of amount of fibre and use of coupling agent with the time of burial in soil. During the preparation of biocomposites, chain scission provoked a similar reduction of M n for coupled and non-coupled biocomposites. The amount of fibre was relevant for the increase of X C due to the increase of nucleation sites. The coupling agent accelerated the evolution of both factors: reduction of M n and the consequent increase of X C , mainly during biodegradation in soil. Both factors should be balanced to facilitate microbial assimilation of polymer segments, since bacterial digestion is enhanced by chain scission but blocked by the promotion of crystalline fractions. [ABSTRACT FROM AUTHOR]

Chicken feathers waste from poultry industry was incorporated in poly(lactic acid) matrix to obtain an environmental friendly biocomposite taking advantage of the unique properties of chicken feathers, such as low density, biodegradability and good thermal and acoustic properties, and of the biodegradability of the poly(lactic acid). The effect of manufacturing conditions on the final properties of the composite and on the matrix–fiber compatibility was studied. Optimal manufacturing conditions, in order to obtain the best mechanical results, were found at a temperature of 170–180℃ for a processing time of 5 min and a speed of mixing of 50 r/min. Young’s modulus was not very affected by the chicken feather’s content showing a maximal variation of less than 8%, indicating that is possible to include chicken feathers in a composite maintaining its stiffness. However, tensile strength and elongation decreased up to 58 and 12%, respectively, when chicken feather content was 25% because of the restraining effect of the fibers. Moreover, dimensional stability was negatively affected with the inclusion of chicken feathers. Infrared spectroscopy and scanning electron microscopy studies show that fiber–matrix interaction exists but it is weak. [ABSTRACT FROM AUTHOR]

Environmental awareness of the global waste problem has driven the development of new green composites made from either renewable or biodegradable materials. Among the variety of available green composites, natural composites based on poly-lactic acid (PLA) have shown noteworthy performance due to their short degradation time after disposal, good strength, and ease of processing by conventional methods. In particular, green composites manufactured with PLA matrix reinforced with Manicaria Saccifera fabric (MF) display mechanical properties that have shown to be very competitive compared with similar materials. In this study, the tensile properties of a green composite of PLA reinforced with MF are optimized by using a Taguchi method approach. The processing parameters, fabric chemical treatment parameters, compression molding parameters, and fiber content are analyzed simultaneously to yield the optimum biocomposite properties. The predicted optimum parameters are experimentally verified. Tensile tests and scanning electron microscope (SEM) analysis are used. Significant improvements on both the tensile strength (114.2%), and the elastic modulus (120.6%) of the biocomposite are achieved. [ABSTRACT FROM AUTHOR]

The objective of this work was to study the biodegradability of polylactic acid (PLA)/paddy straw powder (PSP) biocomposites. Environmental degradation was evaluated by composting the biocomposite samples into the soil. Different techniques, including mechanical tests and scanning electron microscopy (SEM), were used to obtain a view of the degradation that occurred during the soil burial of the biocomposites. Results of the mechanical tests showed that an increasing content of PSP in the biocomposites decreased the tensile strength and elongation at break (EB), while it increased the modulus of elasticity after six months of exposure. Scanning electron microscopy on the surface after soil burial showed that the filler was poorly wetted by the matrix. This explains the reduction in tensile strength and the elongation at break after soil burial. Differential scanning calorimetry results indicated that the crystallinity of the biocomposites increased with longer composting periods. [ABSTRACT FROM AUTHOR]

Biocomposites with tunable properties were successfully prepared through ionic assembly between anionic carboxymethyl cellulose (CMC) and cationic copolymers (quaternized poly( l -lactide)-block-poly N , N -dimethylamino-2-ethyl methacrylate) (PLA- b -PDMAEMA). The quaternized PDMAEMA segment not only works as a compatibilizer between hydrophilic CMC and hydrophobic PLA, but also acts as a lubricant between these two rigid biopolymers. The 1 H NMR (nuclear magnetic resonance) spectra demonstrated successful synthesis of PLA- b -PDMAEMA with controlled molecular weight of PDMAEMA segment. The results from scanning electronic microscopy (SEM) and Fourier transform infrared spectrometry (FTIR) verified the interaction between quaternized copolymer micelles and anionic CMC networks. The resultant biocomposite could form a transparent and uniform film after casting. Both storage moduli and maximum degradation temperature of PLA/CMC composites were increased with the reduction of molecular weight of PDMAEMA segments. It suggests that the properties of biocomposite materials can be tailored by adjusting the chain length of inclusive PDMAEMA segment. [ABSTRACT FROM AUTHOR]

Disposal of Chinese herbal residues (CHRs) during Chinese herbal medicine production and processing has become a problem that requires attention. In this study, CHRs were pretreated by steam explosion or pulverization and composites were prepared by mixing pretreated CHRs with polylactic acid. The mechanical properties of composites of CHRs pretreated by two different methods were compared, the main compositions of CHRs were analyzed, and the morphology of various CHRs and brittle fracture surfaces of composites were observed by scanning electron microscopy. The results show that the mechanical properties of the composites are closely related to the herbal species and pretreatment methods. The mechanical properties of CHR composites pretreated by steam explosion are superior to those pretreated by pulverization. Choosing CHRs with large fiber cell wall–lumen ratio, high lignin and cellulose contents, low contents of hetero cells and hemicellulose are helpful in making composites with good comprehensive performance. [ABSTRACT FROM AUTHOR]

Over recent years, enthusiasm towards the manufacturing of biopolymers has attracted considerable attention due to the rising concern about depleting resources and worsening pollution. Among the biopolymers available in the world, polylactic acid (PLA) is one of the highest biopolymers produced globally and thus, making it suitable for product commercialisation. Therefore, the effectiveness of natural fibre reinforced PLA composite as an alternative material to substitute the non-renewable petroleum-based materials has been examined by researchers. The type of fibre used in fibre/matrix adhesion is very important because it influences the biocomposites' mechanical properties. Besides that, an outline of the present circumstance of natural fibre-reinforced PLA 3D printing, as well as its functions in 4D printing for applications of stimuli-responsive polymers were also discussed. This research paper aims to present the development and conducted studies on PLA-based natural fibre bio-composites over the last decade. This work reviews recent PLA-derived bio-composite research related to PLA synthesis and biodegradation, its properties, processes, challenges and prospects. [ABSTRACT FROM AUTHOR]

The compound of poly(lactic acid) (PLA) and cellulose was made by the emulsion-solvent evaporation technique in order to obtain spheres which are then compression molded to produce a biocomposite film. The effect of the dispersant (poly(vinyl alcohol)—PVA)/PLA ratio on the spheres yield was studied. Moreover, to evaluate the effect of cellulose particle size and surface chemistry on the process yield, unbleached eucalypt kraft pulp and microcrystalline cellulose (MCC), both unmodified and physically or chemically modified were used. PLA/cellulose spheres were characterized regarding its physical properties. It was found that the spheres yield is essentially determined by the PVA/PLA ratio and the percentage of cellulose incorporation is greatly affected by the surface chemistry of cellulose. Regarding the films, DSC runs showed a significant effect of the cellulose type incorporated into PLA matrix on the cold crystallization temperature and on the degree of crystallinity of the biocomposite films. The measurement of tensile properties of the biocomposite films revealed that the strength, elongation at break and toughness (tensile energy absorption at break) of the films incorporating unmodified and chemically modified MCC were substantially improved. [ABSTRACT FROM AUTHOR]