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The present study focuses on the development of biodegradable composites to replace synthetic polymer-based composites for potential lightweight structural applications in the automobile, aeronautical, marine, and packaging industries. Initially, PLA and NFBF/PLA films are prepared by solution casting, and from these films, composite laminates are prepared by film sequencing and compression (hot-press) molding methods. First, the critical buckling load (Pcr) of composites is analyzed, and then, the influence of compressive load on natural frequency is studied. The critical buckling load-bearing capacity of PLA is enhanced with the reinforcement of NFBF (natural fiber braided yarn fabric). The composite with three layers of NFBF registered the highest critical-buckling load (Pcr) of 374.19 N, and this value is 172.13% high compared to the virgin PLA. Similarly, the natural frequency of the NFBF composites approaches minimum when the applied load is equal to the corresponding Pcr. However, a significant increase in the fundamental frequency is noticed when the applied load is higher than the Pcr.

Alginate based biofilms are widely used for designing edible food packaging while its application for developing inedible waterproof food packaging has not been studied enough. Both, cellulose fiber and alginate are attractive natural materials that could be used for developing natural fiber-based food packaging. In this research the cellulose/alginate biocomposites were produced by eco-friendly technique bi-layer lamination of prepared cellulose (C) fiber plates with sodium (SA) and calcium alginates (CA) containing glycerol as plasticizer. The morphology, moisture content, solubility in water, water vapor permeability (WVP), surface hydrophobicity and mechanical characteristics of prepared cellulose/alginates biocomposites were evaluated and compared. The biocomposite surface morphology evaluation showed that all analyzed samples had smooth surfaces without cracks. Moreover, obtained results showed that plasticizer is essential in developing biocomposites with improved characteristics. The concentration of glycerol had a positive effect on gloss, flexibility, moisture content, solubility in water and negative effect to surface hydrophobicity of C/SA and C/CA biocomposites. It was observed that samples had partly hydrophobic surfaces which contact angles varies from 37° to 63°. Mechanical characteristics revealed that the most promising are C/CA biocomposites that could be further modified for waterproof food packaging developing.

For the past few decades environmental concerns had been influencing the researchers to employ natural fibers and polymers from renewable resources as a replacement for petroleum-based resins and synthetic fibers. In this work, materials from renewable resources were used to prepare the composites. Modified epoxidised soybean oil as resin was employed to prepare the composites with chicken feather fibers as the reinforcing agent by compression molding technique. Epoxidised soybean oil (ESO) was modified by reacting with methacrylic acid and methacrylic anhydride to form resin. Rosin acid derivative was synthesized to serve as the crosslinker for replacement of the petroleum based divinylbenzene (DVB). For comparison, divinylbenzene (DVB) was also employed to copolymerize with the same resin. Chemical structure of rosin derivative was verified by 1H-NMR spectroscopy. FT-IR study showed the interaction between resin, chicken feather fiber (CFF) and rosin derivatives. The morphological features of the composites were evaluated by scanning electron microscopy (SEM), where it indicated a uniform interaction among the components of the composites. Different experimental results showed that the composites with higher amount of rosin acid derivative showed better properties. Results demonstrated that rosin acid derivative can serve as a substitute for petroleum-based rigid compounds for preparing biocomposites.

In pursuit of new biobased materials for a sustainable world, glasswort (Salicornia europaea) was utilized in this study as a natural fiber to develop a biocomposite material. Glasswort (GW) reinforced high-density polyethylene (HDPE) composites at different GW percentages were prepared with a high-speed thermo-kinetic mixer. The effect of GW on HDPE composites was thoroughly investigated with Fourier transform infrared (FTIR) spectroscopy, tensile and flexural tests, dynamic mechanical analysis, water contact angle measurements, and scanning electron microscopy (SEM). A new method was also developed by seawater immersion of samples to conduct microbiological analysis. The method included bacteria population count with respect to time. Biointegration was reported to increase as 25% for 20 wt% GW-filled HDPE. The tensile modulus of HDPE increased up to 20% with GW inclusion. The unique properties of this novel composite material proved that GW can be a promising natural fiber for polymer composites.

Biomass–fungi biocomposite materials are derived from sustainable sources and can biodegrade at the end of their service. They can be used to manufacture products that are traditionally made from petroleum-based plastics. There are potential applications for these products in the packaging, furniture, and construction industries. In the biomass–fungi biocomposite materials, the biomass particles (made from agricultural waste such as hemp hurd) act as the substrate, and a network of fungal hyphae grow through and bind the biomass particles together. Typically, molding-based methods are used to manufacture products using these biocomposite materials. Recently, the authors reported a novel extrusion-based 3D printing method using these biocomposite materials. This paper reports a follow-up investigation into the effects of mixing parameters (mixing time and mixing mode) on fungal growth in biomass–fungi mixtures prepared for 3D printing and the effects of printing parameters (printing speed and extrusion pressure) on fungal growth in printed samples. The fungal growth was quantified using the number of fungal colonies that grew from samples. The results show that, when mixing time increased from 15 to 120 s, there was a 52% increase in fungal growth. Changing from continuous to intermittent mixing mode resulted in an 11% increase in fungal growth. Compared to mixtures that were not subjected to printing, samples printed with a high printing speed and high extrusion pressure had a 14.6% reduction in fungal growth, while those with a low printing speed and low extrusion pressure resulted in a 16.5% reduction in fungal growth.

This study investigates the mechanical properties of α-chitin and chitosan biocomposites using molecular dynamics (MD) and stress–strain analyses under uniaxial tensile loading in an aqueous environment. Our models, validated against experimental data, show that α-chitin has a higher directional elastic modulus of 51.76 GPa in the x and 39.76 GPa in the y directions compared to its chitosan biocomposite, with 31.66 GPa and 26.00 GPa in the same directions, demonstrating distinct mechanical behaviors between α-chitin and the biocomposite. The greater mechanical stiffness of α-chitin can be attributed to its highly crystalline molecular structure, offering potential advantages for applications requiring load-bearing capabilities. These findings offer valuable insights for optimizing these materials for specialized applications.

The presented study is focused on the modification of commercially available epoxy resin with flame retardants by means of using natural substances, including quercetin hydrate and potato starch. The main aim was to obtain environmentally friendly material dedicated to rail transport that is resistant to the aging process during exploitation but also more prone to biodegradation in environmental conditions after usage. Starch is a natural biopolymer that can be applied as a pro-ecological filler, which may contribute to degradation in environmental conditions, while quercetin hydrate is able to prevent a composite from premature degradation during exploitation. To determine the aging resistance of the prepared materials, the measurements of hardness, color, mechanical properties and surface free energy were performed before and after solar aging. To assess the mechanical properties of the composite material, one-directional tensile tests were performed for three directions (0, 90, 45 degrees referred to the plate edges). Moreover, the FT-IR spectra of pristine and aged materials were obtained to observe the changes in chemical structure. Furthermore, thermogravimetric analysis was conducted to achieve information about the impact of natural substances on the thermal resistance of the achieved composites.

In this study, we utilized a hybridization approach for two different fibers to overcome the drawbacks of single-fiber-reinforced PLA composites. Coir fiber and bamboo leaf fiber were used as reinforcing natural fibers as their properties complement one another. Additionally, we combined thermal annealing with hybridization techniques to further improve the overall properties of the composites. The results showed that the hybridization of BF: CF with a ratio of 1:2 gave PLA-based hybrid composites optimal mechanical and thermal properties. Furthermore, the improvement in the thermal stability of hybrid composites, attributable to an increase in crystallinity, was a result of thermal annealing. The improvement in HDT in annealed 1BF:2CF hybrid composite was about 13.76% higher than that of the neat PLA. Annealing of the composites led to increased crystallinity, which was confirmed using differential scanning calorimetry (DSC). The synergistic effect of hybridization and annealing, leading to the improvement in the thermal properties, opened up the possibilities for the use of PLA-based composites. In this study, we demonstrated that a combined technique can be utilized as a strategy for improving the properties of 100% biocomposites and help overcome some limitations of the use of PLA in many applications.

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This study investigates eco-friendly membrane biocomposites derived from biomass, utilizing cellulose microfibrils (CMF) as the main membrane material. Cellulose nanocrystals (CNC), isolated from rice husk, were added as reinforcing fillers in CMF flat sheet membranes. CNC with concentrations of 0%, 10%, 20%, and 30% were employed. Scanning electron microscopy images revealed that CNC influenced the surface profile and the pore structure of the membranes, reducing the porosity by 23%. The empty areas formed by CMF interaction were effectively filled by CNC. This modified membrane resulted in an increase in NaCl rejection of up to 16%. Dynamic water contact angle demonstrated the role of CNC in enhancing permeability, with a shorter spreading time of 13 min. It was also confirmed by the highest flux of 351 L/m − 2h−1 under pure water flux conditions. Mechanical properties were significantly improved, with a 125% increase in tensile strength and a modulus of 329 MPa. The distribution of CNC within the membranes filled pores and enhanced CMF interaction, facilitated by abundant hydroxyl groups in CNC. Overall, this study highlights the potential of eco-friendly membrane biocomposites derived from biomass, offering valuable insights for the development of sustainable and efficient membrane materials.

3D-printing or Additive Manufacturing (AM) has been growing as a rapid manufacturing process for many different applications, with Poly (Lactic Acid) as one of the most used materials for 3D-printing. PLA shows great promise for many applications to achieve the goals of the SDGs due to its biodegradability and biocompatibility but lacks when it comes to mechanical strength and thermal resistance. In this study, microcrystalline cellulose (MCC) fibers were introduced as a reinforcement to PLA. The biocomposite filaments were irradiated in a vacuum to enhance the crosslinking. Gamma-ray irradiation in a vacuum has successfully shown signs of crosslinking by increasing the tensile strength and thermal stability of the biocomposite, indicating an enhancement for PLA/MCC for various applications. On the other hand, changes in thermal properties also indicated that irradiation may reduce the processability of the composite, so it is necessary to study the conditions under which the mechanical properties and processability are compatible.

This work highlights the exploitation of fibers from a promising plant, commonly called Diss, in polymer matrix reinforcement. In this context, various untreated and treated (with acetic acid, silane, NaOH, thermal) Diss fibers were used to reinforce a thermoplastic matrix, polypropylene (PP). The effect of fiber treatments was evaluated at a ratio of 10% (by mass) of fiber, using mechanical, microstructural and physical characterization. A fiber content optimization study was carried out after choosing the fiber treatment by varying the fiber content from 10% to 40%. The microstructure observations showed a multi-layer structure for the biocomposites studied. The particular morphology of Diss fibers, with the presence of thorns, seems to improve the mechanical adhesion between the two phases. For 10% fiber content composites, the incorporation of the different fibers in the PP matrix led to improvements in most mechanical properties. The biocomposite reinforced with NaOH treated fibers (NPP-10%) showed the best mechanical performance with an improvement of 30%, 22% and 9% in tensile modulus, bending modulus and bending stress, respectively. For the fiber content variation, the NPP was retained, and an enhancement in the tensile modulus was found when the fiber content was below 20%.

The usage of new cellulosic fibers in industrial applications is massive because of its excellent performances. These fibers are utilized especially for manufacture of high-performance composites. Coconut leaf sheath (CLS) fibers are extracted for leaf sheath of coconut tree. The aim of this paper is to study the possibility of using a natural fiber CLS as an alternative for polymer composites. In the current study, the consequence of NaOH treatment on structural, thermal and morphological behavior of treated and untreated coconut leaf sheath (CLS) fiber in terms of single fiber tensile strength, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (×RD), thermogravimetric analysis (TGA) and differential scanning calorimeter (DSC) has been explored. From SEM analysis, it was identified globular lumps spread consistently over the fiber which could help the mechanical interlock with the resin. The outcomes from the experimentation exposed that the NaOH treatment has impacted in the eradication of amorphous hemicellulose and lignin contents from the CLS fiber surface and in turn resulted in excellent structural and thermal stability behaviour of fiber. The present work endorses the great potential of CLS fibers to be utilized for bio-reinforcement in order to fabricate lightweight composite structures, employed in automobile and structural applications.

Disposable containers made of non-biodegradable polymers are considered as one of the most prevalent environmental pollutants. It is very important and desirable to make fully biodegradable disposable containers for food packaging that does not endanger the health of consumers. In this research, fully biodegradable polymer composites were prepared by melt mixing of polylactic acid (PLA), polybutylene succinate (PBS), and natural polymers including corn starch and wheat straw, and their physical and mechanical properties were evaluated. For this purpose, by conducting experiments according to the optimal custom mixture design of the response surface methodology, the effect of 3 independent variables including the concentration of the PLA and PBS biopolymers blend (50/50% w/w) (CBB) in the range of 30–70, the concentration of corn starch (CCS) in the range of 30–60 and the concentration of wheat straw (CWS) in the range of 0–8 wt percentage of biocomposite on the dependent variables including the elastic modulus (EM), elongation at break (EB), impact strength (IS) and equilibrium moisture content (EMC) of the biocomposite sheet were investigated. According to the results of this research, with the increase in the concentration of corn starch and wheat straw in the studied range, the EM and EMC of the biocomposite increased, while its EB and IS decreased. According to the results obtained from optimizing the effects of independent variables on the physicomechanical properties of the biocomposite sheet, the optimal values predicted by the models for CBB, CCS and CWS were 48.2 wt%, 45.4 wt%, and 6.4 wt%, respectively and predicted values for EM, EB, IS and EMC were 80.8 MPa, 11.4%, 2 kJ/m2 and 4.1%, respectively. Also, the biodegradability rate of the biocomposite with the optimal formulation was 71.1% in the fifth month of the test.

ABSTRACTHygromorph BioComposites (HBC) exhibit shape-changing actuated by a moisture content (MC) variation due to their bilayered bioinspired architecture. However, their application in daily meteorologic variation is limited due to relative humidity (RH) and thermal couplings. This work aims to investigate the role of temperature variation on the shape changing of 4D printed continuous flax fibres reinforced HBC so that ThermoHygromorph BioComposites (THBC) are introduced.The responsiveness of the THBC is governed by the MC of the material and the stiffness ratio between the passive and active layer, which are both thermally dependant. An increase in temperature strongly reduces the actuation amplitude while the actuation kinetics is strongly fastened. A 4D-printed HBC structure is designed and submitted to a practical outdoor environmental loading, to understand the impact of daily RH and temperature variations on THBC actuation.

In this study, a hazelnut shell (HS) filled semi-interpenetrating polymer networks (semi-IPN) biocomposite adsorbent with novel and different compositions was developed that will enable the removal of lead ions, which are commonly found in water, by adsorption reactions. The structural and morphological properties of the produced adsorbents were characterized by FT-IR, XRD, TGA, DSC, BET, FE-SEM, EDX, and zeta potential measurements, and the production mechanism of these adsorbents was discussed. The effects of parameters such as different adsorbent dosages, different heavy metal concentrations, type of adsorbent, contact time, pH, and temperature on the swelling abilities and adsorption properties of adsorbents were investigated in detail. It has been determined that the adsorbent, which exhibits optimum adsorption and swelling properties, is a biocomposite containing 5% by weight HS filler, and it has been observed that it can remove up to 85% of lead ions under different parameters and conditions. In addition, the adsorption behaviors of the produced biocomposites are discussed using isothermal, kinetic, and thermodynamic models. Moreover, studies have been carried out on the reusability of the adsorbent, and it has been observed that the adsorbent produced within the scope of the study is still usable even after four cycles. [ABSTRACT FROM AUTHOR]

As an emerging science, tissue engineering and regenerative medicine focus on developing materials to replace, restore or improve organs or tissues and enhancing the cellular capacity to proliferate, migrate and differentiate into different cell types and specific tissues. Renewable resources have been used to develop new materials, resulting in attempts to produce various environmentally friendly biomaterials. Poly (lactic acid) (PLA) is a biopolymer known to be biodegradable and it is produced from the fermentation of carbohydrates. PLA can be combined with other polymers to produce new biomaterials with suitable physicochemical properties for tissue engineering applications. Here, the advances in modified PLA as tissue engineering materials are discussed in light of its drawbacks, such as biological inertness, low cell adhesion, and low degradation rate, and the efforts conducted to address these challenges toward the design of new enhanced alternative biomaterials. [ABSTRACT FROM AUTHOR]

Astragalus is widely cultivated in China, and the residue of Astragalus particles (ARP) can be used as reinforcements in fused filament-fabricated (FFF) natural fiber/Poly(lactic acid)(PLA) biocomposites. To clarify the degradation behavior of such biocomposites, 3D-printed 11 wt% ARP/PLA samples were buried in soil, and the effects of soil burial duration on the physical appearance, weight, flexural properties, morphology, thermal stability, melting, and crystallization properties were investigated. At the same time, 3D-printed PLA was chosen as a reference. The results showed that, with prolonged soil burial, the transparency of PLA decreased (but not obviously), while the surface photographs of ARP/PLA became gray with some black spots and crevices; especially after 60 days, the color of the samples became extremely heterogeneous. After soil burial, the weight, flexural strength, and flexural modulus of the printed samples all reduced, and greater losses happened to ARP/PLA pieces than pure PLA. With an increase in soil burial time, the glass transition, cold crystallization, and melting temperatures, as well as the thermal stability of PLA and ARP/PLA samples, all increased gradually. Additionally, soil burial had a greater effect on the thermal properties of ARP/PLA. The results showed that the degradation behavior of ARP/PLA was more significantly affected by soil burial than the behavior of PLA. Additionally, ARP/PLA more easily degraded in soil than PLA. [ABSTRACT FROM AUTHOR]

The aim of this work was to improve mechanical properties of a biocomposite of polylactic acid (PLA) reinforcing with fibrillated methacrylate-silanized hemp fibre. The effect of hemp fibre on photo-oxidation and hydrolytic degradation of PLA was evaluated through a QUV accelerated weathering test. Incorporation of 20 mass% fibre filler into neat PLA matrix resulted in increased tensile and flexural modulus for 150% and 200%, respectively. The outdoor degradation of neat PLA and PLA biocomposites was simulated in a 30 days of QUV accelerated weathering test in accordance with ISO 11507 method B. Glass transition temperature (Tg) was periodically recorded to measure the rate of degradation. Differential scanning calorimetry (DSC) analysis indicated that the degradation rate of the PLA matrix of the biocomposites tended to decrease proportionally to exposure time. The statistical regression method revealed a linear relationship between ln(Mn) and lnTg (R2 = 0.96). The 20 mass% hemp/PLA biocomposite was mostly destroyed over neat PLA after 30 days. The rate of degradation tended to have a linear proportion with hemp content. The results of FTIR 13C-NMR analysis confirmed that the substantial degradation of hemp/PLA biocomposites was due to the lignin content of the hemp fibre. The sensitivity of the PLA biocomposite to UVB light and moisture absorption accelerated photo-oxidation and hydrolytic degradation to the lowest molecular weight of PLA. [ABSTRACT FROM AUTHOR]

Extrusion and hot compressing molding processes were used to create bio-polyethylene (BioPE) composites reinforced with argan byproducts (shell, pulp, and argan cake) as bio-fillers. The thermal stability of the composites wass analyzed by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Dynamical mechanical analysis and rheological testing were used to investigate their mechanical properties. The morphological results showed a good adhesion between the argan and BioPE matrix. More efficient mechanical properties have been distinguished in the case of argan byproduct-based composite. A higher Young's modulus was noted for all the biocomposites compared to pure BioPE. Thermal analysis revealed that the addition of bio-filler to polymer reduced decomposition temperatures. This study provides an ecological alternative for upgrading the valorization of abundant and underutilized Moroccan biomass. Furthermore, the possibility of using argan byproducts in composite manufacturing will help open up new markets for what is currently considered waste. [ABSTRACT FROM AUTHOR]

When developing new innovative building materials, their performance characteristics as well as their environmental friendliness are important. It is difficult to produce a fully ecological material for building envelopes, because there is a lack of ecological binding materials on the market, good binding materials are very expensive, and cheaper ones have poorer adhesive properties and performance characteristics. In this work, natural organic sapropel was used as an ecological binder. Before use, an organic sapropel was additionally mechanically activated. Its activation efficiency was evaluated on the basis of consistency and tensile strength. Sapropel activation increased its consistency from 112 to 168 mm and its tensile strength from 466 to 958 kPa. Wood processing waste was used as a filler for the thermal insulation biocomposite. Additionally, the wood waste was chopped to regulate the density and main performance properties of the biocomposite. The density of the biocomposite was also regulated using different amounts of sapropel and the degree of compaction of the composite mixture. In this work, the influence of the amount of sapropel, the level of compression of the biocomposite mixture, and the size of the wood waste particles on the thermal conductivity and compressive stress of the biocomposite was analyzed. It was found that the compression level had the greatest influence on both the compressive stress and thermal conductivity, up to 12 times and 43.3%, respectively. [ABSTRACT FROM AUTHOR]

In most cases, plant containers used in the horticulture industry are not reusable, have many negative impacts on the environment, and take a long time to degrade. To reduce the use of non-biodegradable plant containers, many bio-degradable plant containers have been developed for the horticulture industry. However, the full potential of the sustainability of plant containers is yet to be completely explored. Therefore, two novel biodegradable plant containers are developed in this research to effectively contribute to sustainability's environmental, social, and economic dimensions. The two biocomposite formulations are developed by mixing soy hull and soy protein isolate (SPI) with polylactic acid (PLA) matrix for plant containers. In the first formulation, the proportion of PLA and soy hulls are 70 wt% and 30 wt%, respectively; in the second formulation, 65 wt% PLA is blended with 30 wt% soy hulls and 5 wt% SPI. The injection molding process is used to manufacture the plant containers from the two formulations. In a field trial, four plant species are grown in the novel plant containers along with polyethylene and commercial PLA/DDGS (dried distiller's grains with solubles and PLA-based container) containers to investigate biodegradability and plant growth. The results show that the containers from the new formulations outperform existing biodegradable PLA/DDGS containers in terms of certain plant growth and biodegradability. [ABSTRACT FROM AUTHOR]

Natural bone healing is often inadequate to treat fractures with critical size bone defects and massive bone loss. Immediate surgical interventions through bone grafts have been found to be essential on such occasions. Naturally harvested bone grafts, although are the preferred choice of the surgeons; they suffer from serious clinical limitations, including disease transmission, donor site morbidity, limited supply of graft etc. Synthetic bone grafts, on the other hand, offer a more clinically appealing approach to decode the pathways of bone repair through use of tissue engineered biomaterials. This article critically retrospects the translational research on various engineered biomaterials towards bringing transformative changes in orthopaedic healthcare. The first section of the article discusses about composition and ultrastructure of bone along with the global perspectives on statistical escalation of bone fracture surgeries requiring use of bone grafts. The next section reviews the types, benefits and challenges of various natural and synthetic bone grafts. An overview of clinically relevant biomaterials from traditionally used metallic, bioceramic, and biopolymeric biomaterials to new generation composites have been summarised. Finally, this narrative review concludes with the discussion on the emerging trends and future perspectives of the promising bone grafts. [ABSTRACT FROM AUTHOR]

The increasing concerns about plastic pollution and climate change have encouraged research into bioderived and biodegradable materials. Much attention has been focused on nanocellulose due to its abundance, biodegradability, and excellent mechanical properties. Nanocellulose-based biocomposites are a viable option to fabricate functional and sustainable materials for important engineering applications. This review addresses the most recent advances in composites, with a particular focus on biopolymer matrices such as starch, chitosan, polylactic acid, and polyvinyl alcohol. Additionally, the effects of the processing methods, the influence of additives, and the outturn of nanocellulose surface modification on the biocomposite's properties are outlined in detail. Moreover, the change in the composites' morphological, mechanical, and other physiochemical properties due to reinforcement loading is reviewed. Further, mechanical strength, thermal resistance, and the oxygen–water vapor barrier properties are enhanced with the incorporation of nanocellulose into biopolymer matrices. Furthermore, the life cycle assessment of nanocellulose and composites were considered to analyze their environmental profile. The sustainability of this alternative material is compared through different preparation routes and options. [ABSTRACT FROM AUTHOR]

This article speculated the physical, mechanical, tribological, and surface morphology of the coir filler-reinforced polymeric composite. The investigation has been carried out regarding different weight percentages (2.5%, 5%, 7.5%, 10% and 12.5%) of coir filler. Moreover, a novel framework for inferring the optimal reinforcement condition of coir in epoxy resin has also been proposed in the form of Schweizer–Sklar fuzzy TOmada de Decisão Interativa e Multicritério (TODIM) approach. The proposed framework is reliable as it does away with the expert's biased evaluations and gives due consideration to their risk appetite. The optimal reinforcement condition has been deduced with due consideration to tribological, tensile, flexural and fracture properties of the fabricated composites. Through the investigation, it has been observed that the polymeric composite fabricated using 5 wt.% coir filler yields the most favourable results with regard to the considered mechanical and tribological properties. [ABSTRACT FROM AUTHOR]

Biobased composites offer unique properties in the context of sustainable material production as well as end-of-life disposal, which places them as viable alternatives to fossil-fuel-based materials. However, the large-scale application of these materials in product design is hindered by their perceptual handicaps and understanding the mechanism of biobased composite perception, and its constituents could pave the way to creating commercially successful biobased composites. This study examines the role of bimodal (visual and tactile) sensory evaluation in the formation of biobased composite perception through the Semantic Differential method. It is observed that the biobased composites could be grouped into different clusters based on the dominance and interplay of various senses in perception forming. Attributes such as Natural, Beautiful, and Valuable are seen to correlate with each other positively and are influenced by both visual and tactile characteristics of the biobased composites. Attributes such as Complex, Interesting, and Unusual are also positively correlated but dominated by visual stimuli. The perceptual relationships and components of beauty, naturality, and value and their constituent attributes are identified, along with the visual and tactile characteristics that influence these assessments. Material design leveraging these biobased composite characteristics could lead to the creation of sustainable materials that would be more attractive to designers and consumers. [ABSTRACT FROM AUTHOR]

Bio-derived epoxy green composites were fabricated using waste tea fibers and their durability was studied under aggressive environments. The fibers were first mercerized and subsequently functionalized with maleic anhydride. Functionalization resulted in improved adhesion as well as uniform distribution of the fibers in the matrix. Although, the tensile strength was lower than the pristine, improvements were recorded in their mechanical strengths (tensile strength up to 16.1 MPa) compared to un-modified ones, with good elongation at break (23.8%). The green composites also demonstrated good thermal stability up to 244 °C. On investigating the durability toward disparate chemical and physical environments, all the materials exhibited high resistance under extreme temperatures (2 and 70 °C) and UV irradiation and showed remarkable enhancements in tensile strength after aging (up to 65.8% and 49.5%, respectively). This study ensured promising outdoor applications of this green composite derived using waste materials as a benign durable material. [ABSTRACT FROM AUTHOR]

Foam-formed cellulose biocomposites are a promising technology for developing lightweight and sustainable packaging materials. In this work, we produce and characterize biocomposite foams based on methylcellulose (MC), cellulose fibers (CF), and lignin (LN). The results indicate that adding organosolv lignin to a foam prepared using MC and CF moderately increases Young's modulus, protects the foam from the growth of Escherichia coli bacteria, and improves the hydrophobicity of the foam surface. This article concludes that organosolv lignin enhances many properties of cellulose biocomposite foams that are required in applications such as insulation, packaging, and cushioning. The optimization of the foam composition offers research directions toward the upscaling of the material solution to the industrial scale. [ABSTRACT FROM AUTHOR]

Climacteric rise in the rate of respiration and ethylene production in harvested persimmon (Diospyros kaki) fruits leads to early onset of fruit tissue senescence. Therefore, this study was carried out to maintain the quality of stored persimmons by using edible coatings. For this purpose, Aloe vera gel was combined with food hydrocolloids, gum arabic or tragacanth gum, and applied on persimmon fruits that were stored for 20 days at 20 ± 1 °C and 80–85% RH. Biocomposite coatings, compared to control, remarkably reduced weight loss, decay incidence, respiration rate, ethylene production, electrolyte leakage, malondialdehyde, H2O2 and superoxide anion content in stored fruits. The use of composite coatings inhibited colour change by reducing the accumulation of total carotenoids, maintained higher antioxidative enzymes activity and suppressed the activity of cell wall degrading enzymes, resultantly preserving cell wall components. Composite coated fruits exhibited the least change in biochemical attributes and higher sensory scores in comparison with non-coated fruits at the end of the storage period. In conclusion, Aloe vera gel/gum arabic was the most effective coating treatment before storing persimmons. [ABSTRACT FROM AUTHOR]

In the era of growing plastic consumption, food waste by consumers and overproduction caused by economic reasons, the global goal is to decrease these phenomena. Biocomposite films investigated in the past years are creating a promising future toward ecological, intelligent and active packaging. Due to their unique properties, they can be used in many areas of our life and reduce the constantly increasing pollution of our planet. The aim of our study was to obtain innovative and flexible biopolymer films based on sodium alginate and chitosan, as well as to develop methods for generating nanocapsules with turmeric extract in them. Bionanocomposites were analyzed using UV-VIS, FTIR, photoluminescence spectroscopy and SEM microscopy, while contact angles, surface free energy, particle size (DLS) and zeta potential were determined. The mechanical and colorimetric properties of the produced films were investigated, and the water content, solubility and water absorption were determined. Microbiological tests were carried out to analyze the influence of the produced films on the development of microorganisms. The results of the performed analyses allowed us to confirm the presence of curcumin nano- and microcapsules in the alginate–chitosan composite. Moreover, studies have shown that the structure of polysaccharides does not change during capsule manufacturing. The film with the highest concentration of the capsules showed better parameters in tests of solubility, water content, degree of swelling and mechanical properties. The obtained properties of the developed films allow them to be used as active and intelligent packaging materials, or as their parts. [ABSTRACT FROM AUTHOR]

Over hundreds of millions of years, organisms have evolved architected structures via precise control over hierarchically assembled components, including the integration of dissimilar materials. One such example is found in the radula system of chitons, intertidal mollusks that feed on algae growing on the rock. Their radula consists of multiple rows of ultrahard teeth, each integrated with a foldable belt-like substrate via a stiff, yet flexible stylus, which is essential for efficient rasping during the feeding process. Here, we investigate the nano and micro-scale components and architectures as well as regional mechanical properties of the stylus, and their subsequent role during the rasping of Cryptochiton stelleri. Three important factors were determined to contribute to the regio-specific stiffness of the stylus: the presence of mineral components, highly oriented chitinous fibers, and a chemically cross-linked protein matrix. All these factors are varied throughout the stylus. There is a high mineral content on the trailing edge close to the tooth and a cross-linked matrix on the leading edge, both with orientational specific oriented chitin fibers that provide force transduction to the tooth. Conversely, there is a significant lack of mineral or cross-linked matrix in the proximal end as well as a low degree of fiber orientation, resulting in a flexible region that can accommodate torsion and flexure during rasping. Understanding the graded composite structure of the stylus and applying this unique design to various engineering fields such as soft robotics, biotechnology, and the medical industry, can inspire the production of high-performance materials. Graphical Abstract [ABSTRACT FROM AUTHOR]

In order to further explore the feasibility of the application of the residue of Chinese herbal medicine in FDM 3D technology and enrich the kinds of printing materials, Astragalus residue powder(ARP)/poly(lactic acid) (PLA) biocomposite was FDM 3D-printed, meanwhile, two traditional biocomposites, i.e., wood flour (WF)/PLA and rice straw powder (RSP)/PLA, were prepared by the same method, and the properties of the biocomposites were comparatively investigated. The results showed that, the tensile and flexural strengths of ARP/PLA were 28.33 MPa and 97.60 MPa, respectively, which were 2.85% and 10.89% smaller than those of WF/PLA, while 15.73% and 7.04% greater than those of RSP/PLA. WF/PLA showed typical brittle fracture characteristics, ARP/PLA and RSP/PLA both showed ductile fracture, but not obviously. Among the three kinds of biocomposites, ARP/PLA was the most thermally stable, followed by WF/PLA and RSP/PLA in turn. The incorporation of natural plant powder had no significant effect on the glassy transition, melting, and cold-crystallization behaviors of PLA, but the crystallinity of PLA could be increased from 0.3% to 2.0% and 1.9%, respectively, by adding ARP and WF. At 20 °C, the storage modulus of ARP/PLA, WF/PLA and RSP/PLA was 2759.4 MPa, 3361.3 MPa, and 2691.5 MPa, respectively, indicating that WF/PLA has the greatest stiffness, and the stiffness of RSP/PLA was the least. In addition to these, all the biocomposites were hydrophilic, the contact angle of the distilled water on the surface of ARP/PLA, WF/PLA or RSP/PLA was correspondingly 73.5°, 77.6° and 71.2°. Overall, it can be concluded that ARP/PLA has moderate strengths, stiffness and wettability, meanwhile, it is the most thermal stable among the three biocomposites, and can be processed at a temperature close to that of PLA. ARP/PLA is suitable as a new kind of feedstock material for FDM 3D printing. [ABSTRACT FROM AUTHOR]

Optimization of the print setting is important to achieve the desired product characteristics, which, in turn, reduce the effort of the manufacturer and the cost of production. Natural fiber reinforced PETG composites can be a potential 3D printing raw material for additive manufacturing of medical products like scaffolds, implants, prostheses, and orthoses. But the process parameters of this unique composite material need to be optimized for the fabrication of complex structures. Here, PETG-silk fibroin (PETG-SF) composites were printed by optimizing the process parameters based on single and multi-objective optimization techniques for responses such as minimum porosity, maximum dimensional accuracy, and maximum yield load. For accurate measurement of porosity and dimensional accuracy, micro-CT analysis was employed. Single objective optimization results indicate layer height and printing temperature as the highest contributing factor for maximum dimensional accuracy, maximum yield load, and for minimum porosity. Multi objective optimization result shows high temperature, low layer height, and low speed are the best settings for minimum porosity, maximum yield load, and maximum dimensional accuracy. Finally, the optimized parameters were used to print an organic shaped object to validate the results for the production of patient specific anatomically conformed prosthesis and implants. Altogether, our results show that the process parameters have a significant influence on the 3D printing of natural fiber reinforced composites and a complex structure can be effectively fabricated with the optimized parameter settings. [ABSTRACT FROM AUTHOR]

The mechanical properties of natural fibers, as used to produce sustainable biocomposites, vary significantly—both among different plant species and also within a single species. All plants, however, share a common microstructural fingerprint. They are built up by only a handful of constituents, most importantly cellulose. Through continuum micromechanics multiscale modeling, the mechanical behavior of cellulose nanofibrils is herein upscaled to the technical fiber level, considering 26 different commonly used plants. Model-predicted stiffness and elastic limit bounds, respectively, frame published experimental ones. This validates the model and corroborates that plant-specific physicochemical properties, such as microfibril angle and cellulose content, govern the mechanical fiber performance. [ABSTRACT FROM AUTHOR]

This study explores the possibility of developing a new class of hybrid particulate-filled biocomposites using wood flour and rice husk wastes as environmentally friendly additives to poly(lactic acid) (PLA) as matrix material. Samples were prepared with fillers of different concentrations (0, 2.5, 5, 7.5 and 10 wt %), while the ratio of wood flour and rice husk was fixed at 1:1 in all cases. The preparation of biocomposites was performed through extrusion using a twin-screw extruder. Subsequently, they were formed into specimens by injection molding. Mechanical, thermal, thermomechanical, and morphological properties were examined. The addition of natural waste particles resulted in a remarkable improvement both in tensile and flexural modulus; however at a cost of impact strength and tensile strength. Meanwhile, flexural stress at conventional strain values were barely affected by the presence of wood flour and rice husk. The SEM images confirmed that there is a limited interfacial adhesion between the components, which supports the results obtained during mechanical tests. Both the differential scanning calorimetry (DSC) and the dynamic mechanical analysis indicated that the glass transition temperature of PLA was not affected by the incorporation of filler particles; however, the crystalline structure was gradually altered with increasing filler loading according to the DSC. Additionally, the particles were observed acting as nucleating agents, thereby increasing the overall crystallinity of PLA. [ABSTRACT FROM AUTHOR]

Green nanocomposites based on polylactic acid (PLA) and Wood Flour (WF) with different loadings of graphene nanoparticles (GNPs) were produced by compressing molding process. The mechanical strength, dimensional stability, and viscoelastic behavior of nanocomposites were characterized by static mechanical analysis (flexural and tensile), water uptake, and dynamic mechanical analysis (DMA) tests. Results indicated that the incorporation of GNPS into the fabricated samples, significantly improved the mechanical properties of the composites. However, the water absorption and thickness swelling of the composites progressively decreased with increasing GNPs content. In general, the specimens filled with GNPs showed the highest values of storage and loss modulus compared with the other ones, due to the highest interaction taking place at the matrix–filler interface. Morphological images show that the GNPs were homogeneously and well-dispersed in the composites. Based on the findings obtained from the present study, it can be said that the optimum content of GNPs for the fabricated WPC samples is 2%. [ABSTRACT FROM AUTHOR]

This study focused on the development of a novel biocomposite material formed by a thermoplastic biodegradable polyester, poly(butylene succinate-co-adipate) (PBSA), and a carbonaceous filler as biochar (BC) derived by the pyrolysis of woody biomass waste. Composites with various BC contents (5, 10, 15, and 20 wt.%) were obtained by melt extrusion and investigated in terms of their processability, thermal, rheological, and mechanical properties. In all the composites, BC lowered melt viscosity, behaving as a lubricant, and enhancing composite extrudability and injection moulding at high temperatures up to 20 wt.% of biochar. While the use of biochar did not significantly change composite thermal stability, it increased its stiffness (Young modulus). Differential scanning calorimeter (DSC) revealed the presence of a second crystal phase induced by the filler addition. Furthermore, results suggest that biochar may form a particle network that hinders polymer chain disentanglement, reducing polymer flexibility. A biochar content of 10 wt.% was selected as the best trade-off concentration to improve the composite processability and cost competitiveness without compromising excessively the tensile properties. The findings support the use of biochar as a sustainable renewable filler and pigment for PBSA. Biochar is a suitable candidate to replace more traditional carbon black pigments for the production of biodegradable and inexpensive innovative PBSA composites with potential fertilizing properties to be used in agricultural applications. [ABSTRACT FROM AUTHOR]

In this study, one high-performance hemicelluloses (HC)-based sprayable and biodegradable pesticide mulch film was developed. Firstly, HC was transesterified with vinyl acetate (VA) to improve its solubility and film-forming ability. Then abamectin (ABA) was encapsulated by β-cyclodextrin (β-CD) to endow mulch film persistent anti-pesticide activity. After that, sodium alginate (SA) and gelatin were added to develop the mechanical performances of the mulch film. As a result, the obtained mulch film showed good characteristics, with optimum mechanical strength, elongation at break, water vapor permeability (WVP), swelling ratio (SR), and weight loss (biodegradability) of 7.9 ± 0.3 MPa, 43.6 ± 2.0 %, 2.1 ± 0.1 × 10−11 g mm m−2 s−1 kPa−1, 73.8 ± 2.0 %, and 69.3 %, respectively. After covering with mulch film, the soil moisture and temperature were developed to 90.8 % and 19.3 ± 0.2 °C, respectively, which could facilitate Chinese cabbage growth, with optimum germination rate of 98.6 ± 6.4 %. [Display omitted] • Hemicelluloses-based sprayable pesticide mulch films were successfully developed. • Abamectin-loaded β-CDs were incorporated to give films sustained anti-insect ability. • The films had good water retention ability, mechanical strength and biodegradability. • The films improved the soil temperature and moisture, facilitating cabbage growth. [ABSTRACT FROM AUTHOR]

The present work highlights the preparation of the epoxidized natural rubber conjugated spent coffee biocomposites (ENR‐g‐SC) via one‐pot synthesis to control petroleum oil spills. The structural determination of the spent coffee grafted epoxidized natural rubber (ENR‐g‐SC) was confirmed through FTIR and 1H‐NMR spectroscopic analyses. The thermal performance, tensile tests, and morphological properties of the synthesized (ENR‐g‐SC) biocomposites were performed. The data revealed that ENR‐g‐SC biocomposite with 20 phr of spent coffee (SC) exhibited the highest tensile properties due to maximal chemical linkages of spent coffee and epoxide groups in ENR. The epoxidized natural rubber conjugated spent coffee copolymers were evaluated as oil sorbers for oil absorbency applications in chloroform, toluene, and 10% crude petroleum diluted with toluene. The data revealed that the oil absorbency increased slightly with chloroform or toluene instead of 10% crude oil diluted with toluene. Furthermore, swelling and network parameters including the maximum oil absorbency (Qmax), swelling rate constant (k), polymer‐solvent interaction (χ), effective crosslink density (ύe), equilibrium modulus of elasticity (GT), and average molecular weight between crosslinks (Mc) and theoretical crosslink density (ύt) were determined, and correlated to the efficiency of the synthesized epoxidized natural rubber conjugated spent coffee. [ABSTRACT FROM AUTHOR]

An ever‐increasing rise in demand for sustainable materials has received significant attention in developing biocomposites for structural applications. In this regard, natural fibers replacing synthetic fibers as reinforcement in epoxy composite could be a significant gain toward sustainability, especially in automobile and structural applications. Herein, flax fiber/cellulose paper–reinforced epoxy biocomposite (FREC‐X) was fabricated via a vacuum infusion process. The influence of postcuring conditions (time and temperature) and cellulose paper density on the mechanical properties of FREC‐X was studied. The tensile strength and modulus of FREC‐X increased by 37% and 64%, respectively, upon the integration of paper. Postcuring FREC‐X further augmented the tensile and flexural properties of the composite, which could be attributed to the increase in cross‐linking of the epoxy and yields a strong polymer network. Fractography analysis confirmed that the composites integrated with paper showed fewer defects with improved interfacial adhesion. In addition, the water absorption and thickness swelling results revealed that the presence of cellulose paper marginally increased the water uptake and thickness swelling of FREC‐X. Furthermore, there was no significant change in the tensile and flexural properties of FREC‐X observed even after immersing in water for >200 h. Such properties of FREC‐X seen as a fascinating alternative to synthetic fibers and petroleum‐based epoxy and are promising material for sustainable development. [ABSTRACT FROM AUTHOR]

A new class of biobased composites with tailorable mechanical properties made of natural fibers, polylactic acid, and ferulic acid derivatives (FAD) is studied. FAD was used to develop composites with elastomeric properties like improved elongation at break and highly reversible deformation upon elongation. Composites were prepared using raw and enzymatically treated hemp fibers. The fibers were defibrillated due to the enzymatic treatment increasing their aspect ratio. The composites were characterized by their mechanical properties and their reaction to fire. No significant change in the dispersion of the fibers in the composites was reported. Homogenously dispersed crystallites of FAD were observed by scanning electron microscopy in the PLA matrix and at the interface between the PLA and the fibers, where they are suspected to increase the free volume in correlation with a decrease in mechanical properties following the increase in the aspect ratio of the fibers. FAD also degraded the reaction to fire of the material with an increase in 10% of the peak of Heat Release Rate (pHRR) in comparison to neat PLA. It also increased the charring residue up to 3 wt.%. A synergistic effect between FAD and the lignin increasing the charring residue is also reported. [ABSTRACT FROM AUTHOR]

The usage of new cellulosic fibers in industrial applications is massive because of its excellent performances. These fibers are utilized especially for manufacture of high-performance composites. Coconut leaf sheath (CLS) fibers are extracted for leaf sheath of coconut tree. The aim of this paper is to study the possibility of using a natural fiber CLS as an alternative for polymer composites. In the current study, the consequence of NaOH treatment on structural, thermal and morphological behavior of treated and untreated coconut leaf sheath (CLS) fiber in terms of single fiber tensile strength, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (×RD), ther)mogravimetric analysis (TGA) and differential scanning calorimeter (DSC) has been explored. From SEM analysis, it was identified globular lumps spread consistently over the fiber which could help the mechanical interlock with the resin. The outcomes from the experimentation exposed that the NaOH treatment has impacted in the eradication of amorphous hemicellulose and lignin contents from the CLS fiber surface and in turn resulted in excellent structural and thermal stability behaviour of fiber. The present work endorses the great potential of CLS fibers to be utilized for bio-reinforcement in order to fabricate lightweight composite structures, employed in automobile and structural applications. [ABSTRACT FROM AUTHOR]

This work highlights the exploitation of fibers from a promising plant, commonly called Diss, in polymer matrix reinforcement. In this context, various untreated and treated (with acetic acid, silane, NaOH, thermal) Diss fibers were used to reinforce a thermoplastic matrix, polypropylene (PP). The effect of fiber treatments was evaluated at a ratio of 10% (by mass) of fiber, using mechanical, microstructural and physical characterization. A fiber content optimization study was carried out after choosing the fiber treatment by varying the fiber content from 10% to 40%. The microstructure observations showed a multi-layer structure for the biocomposites studied. The particular morphology of Diss fibers, with the presence of thorns, seems to improve the mechanical adhesion between the two phases. For 10% fiber content composites, the incorporation of the different fibers in the PP matrix led to improvements in most mechanical properties. The biocomposite reinforced with NaOH treated fibers (NPP-10%) showed the best mechanical performance with an improvement of 30%, 22% and 9% in tensile modulus, bending modulus and bending stress, respectively. For the fiber content variation, the NPP was retained, and an enhancement in the tensile modulus was found when the fiber content was below 20%. [ABSTRACT FROM AUTHOR]