Bio-based Composites Research Articles

Use of a commingling process for innovative flax fibre reinforced unidirectional composites

Optimisation of textile preforms play a crucial role in the development of high-performance biobased composites materials. In this context, the main ambition of this work is to quantify and assess the mechanical properties and behaviour of biocomposite materials made from unidirectional commingled preforms based on flax and poly-(propylene) fibres. To the best of our knowledge, there is no literature examining the effect of the commingling process on the ultrastructure and the mechanical properties of flax fibres. At the scale of the elementary fibre, fibre mechanical properties are observed to be stable after commingling. However, repeated drawing in the commingling process leads to increased cellulose crystallinity and a larger fraction of elementary fibres exhibiting quasi-linear tensile behaviour. The composite materials produced with these commingled flax/poly-(propylene) preforms contain few cortical residues and show a remarkable degree of fibre individualisation. Moreover, they exhibit high Young's modulus and a stress at break of 24 GPa and 194 MPa, respectively, for a fibre volume fraction of 36 %. A substantial drop in properties is however noted at high fibre fractions due increased heterogeneity of the materials. Remarkably, the biocomposites achieved unprecedented transverse modulus and stress at break of 2.3 GPa and 16.5 MPa, respectively. Our results validate the potential and interest in commingling processes for designing a new family of plant fibre composite materials.

Bio-based Eucommia ulmoides gum composites for high-performance engineering tire applications

In this work, bio-based Eucommia ulmoides gum (EUG)/natural rubber (NR)/styrene-butadiene rubber (SBR) composites are successfully fabricated through physical blending. The influence of sulfur (S) and EUG content on the crystallization characteristics, static and dynamic mechanical properties of the composites is systematically investigated. Furthermore, the impact of the cross-linking network structure on the crystallization behavior of EUG is examined, and the application of EUG/NR/SBR composites in engineering tires is explored. The results reveal that with the increasing of EUG content, the composites exhibit enhanced wear resistance and cut resistance, as well as reduced heat generation and rolling resistance. Specifically, in comparison with NR/SBR composites, the dynamic temperature rise, wear resistance, and dynamic cutting amount of EUG/NR/SBR (20/40/40) composites decreased by 14.7%, 17.1%, and 11.2%, respectively, while the fatigue life of the composites improves by 33%. This work provides valuable guidance for fabricating and applying high-performance bio-based EUG composites in engineering tires.

Interfacial properties of carbon fiber‐reinforced biobased resin composites by single fiber fragmentation, fiber push‐out, and interlaminar shear strength

AbstractThe present study examines the interfacial properties of carbon fiber biobased resin composites by comparing the test methods such as the single fiber fragmentation test, fiber push‐out test, and interlaminar shear strength test. The composites were fabricated using a cold vacuum‐assisted resin infusion method for the preparation of fiber push‐out and interlaminar shear test specimens. The interfacial adhesion from the three different test methods is analyzed and compared to determine their relative effectiveness in evaluating interfacial adhesion. Plasma treatment is performed on the carbon fibers and the interfacial shear stress is evaluated by conducting the push‐out test. The surface characterization of the carbon fibers is done by scanning electron microscopy and x‐ray photoelectron spectroscopy to investigate the influence of the plasma treatment on the fiber surface. Plasma treatment resulted in significant improvement in the interfacial adhesion between the fiber and matrix.Highlights Analysis and comparison of interfacial adhesion by several test methods. Single fiber fragmentation and push‐out tests with IFSS of 40.5 and 42.2 MPa. Plasma surface treatment improved the IFSS by 88.1%. Surface characterization of treated and untreated fibers by SEM and XPS.

3-D modeling of automatic pressure gelation process for manufacturing gas insulated switchgear spacer using bio-based epoxy composite

In existing power devices, various insulating parts are manufactured with petroleum-based epoxy resin. However, as petroleum-based resources are gradually depleted and environmental problems have emerged, research on replacing petroleum-based products with eco-friendly materials as insulators has been actively conducted. Therefore, in this study, a molding simulation study of the Auto Pressure Gelation (APG) process, one of the leading technologies, was conducted to manufacture a gas insulated switchgear (GIS) spacer using an environmentally friendly bio-based epoxy composite. Using the heat dissipation and degree of cure obtained through the dynamic differential scanning calorimetry (DSC) test, it was applied to the Kamal-Sourour model which is a representative curing dynamics empirical formula. In addition, the viscosity change during the curing process was measured using a rheometer and applied to the cross Castro-Macoskco model. The results obtained were in good agreement with the experimental values. The parameters calculated above and other physical property values were input into Moldflow software, and simulation was performed targeting the three-phase spacer. While changing the temperature setting of the mold, the change and distribution of flow, temperature, and curing degree inside the product were observed during the reactive molding process. As a result, it was found that there was a possibility of clogging of the mold entrance at some set temperatures, and it was possible to suggest improvement directions to solve this problem. Through this series of research process, it is considered that it will be of great help in improving the quality problems of molded products and the process accordingly.

Improvements in Mechanical and Shape-Memory Properties of Bio-Based Composite: Effects of Adding Carbon Fiber and Graphene Nanoparticles.

Shape-memory carbon fiber (CF) polymer composites reinforced with graphene nanoplatelets (GnPs) as a filler based on a bio-based V-fa/ECO copolymer were prepared at different graphene GnPs and CF mass fractions using the hand lay-up and hot-pressing methods. The obtained composite specimens were subjected to flexural, dynamic mechanical, and shape-memory analyses. The obtained results revealed that the flexural strength and modulus were improved by the addition of the GnPs and CF due to the improvement in the interfacial adhesion and fiber reinforcement with up to 3 wt.% GnPs and 60 wt.% CF. Additionally, appreciable improvements in the shape-memory performance were achieved with the addition of the GnPs, where values of up to 93% and 96% were recorded for the shape fixity and recovery, respectively. The shape-memory performance was affected by the fiber mass fraction, with the composites retaining the shape-memory effect albeit with a significant drop in performance at higher fiber mass fractions. Lastly, the specimens at 40 wt.% CF and 3 wt.% GnPs were determined to be the optimum compositions for the best performance of the bio-based SMP composite.

Microwave-Assisted Chemical Purification and Ultrasonication for Extraction of Nano-Fibrillated Cellulose from Potato Peel Waste

Nanofibrillated cellulose was extracted from potato peel waste using a fast and green method with a simple process. To extract cellulose and eliminate non-cellulosic constituents, alkaline and hydrogen peroxide treatments were performed under microwave irradiation. The nanofibrillated cellulose was extracted from purified cellulose via TEMPO oxidation followed by ultrasonication. The TEM, FTIR, XRD, and TGA experiments were used to evaluate the structural, crystalline, and thermal properties of cellulose fiber and nanofiber. The chemical and FTIR analysis of bleached fibers indicates that almost all non-cellulosic components of biomass have been eliminated. The diameter of the extracted nanofibers is in the range of 4 to 22 nm. In terms of crystallinity, extracted nanocellulose had 70% crystallinity, compared to 17% for unprocessed lignocellulose fibers, which makes it an excellent choice for use as a reinforcement phase in biobased composites. Thermogravimetric analysis reveals that cellulose nanofibers are less thermally stable than potato peel pure cellulose, but it has a higher char content (28%) than pure cellulose (6%), which signifies that the carboxylate functionality acts as a flame retardant. The comparison between cellulose derived from microwave and conventional extraction methods confirmed that their impact on the removal of non-cellulosic materials is nearly identical.

A Comparative Life Cycle Assessment of a New Cellulose-Based Composite and Glass Fibre Reinforced Composites

The use of renewable lightweight materials and the adoption of cleaner production are two effective approaches to reduce resource consumption, which contributes to meeting the industry’s environmental impact targets. In a previous study we found, that a miscanthus fibre reinforced cellulose acetate (CA-Miscanthus, 25 wt.%) can be a bio-based alternative to glass fibre reinforced polypropylene (PP-GF, 20 wt.%), as both materials exhibit similar mechanical properties. However, only limited information on the environmental benefits of using bio-based composites instead of their petroleum-based counterparts are available. In this study, we compare the environmental impact of ready to use compound of both materials in the cradle to gate system boundaries, including fibre cultivation, fractionation and refining, fibre pretreatment, and compounding. The functional unit is chosen based on the equivalent function of both materials. The environmental impact is determined using the Product Environmental Footprint (PEF) methodology. The results reveal that the CA-Mis composite has a higher environmental impact than the PP-GF composite in all categories observed, despite its biomass origin. As the primary reason for the high impact, the acetic anhydride use during CA production is identified. The study indicates that, though the bio-composite CA-Mis has mechanical properties comparable to PP-GF composites, it is not as eco-friendly as we initially assumed it to be.

Self-healing recyclable bio-based magnetic composites with boronic ester vitrimer matrix

The ongoing energy crisis and increasing consumption of fossil-based feedstock have raised the awareness of researchers about the need to develop sustainable alternatives for conventional plastic materials. A great potential is attributed to vitrimers, a newly emerging class of polymer materials that, despite being covalently cross-linked, can be easily repaired, reprocessed, or recycled with minimal environmental impact. Such properties are achieved due to dynamic cross-links that enable the reversible reactions within their network structure. Here, we report on the development of a novel bio-based magnetic composite by adopting the catalyst-free vitrimer as a host matrix for embedding the magnetic micro-filler. The employed matrix uses a recent generation of the exchange reactions ensured by boronic ester metathesis, following the principles of “green” chemistry. The final composite is endowed with various useful, programmable, and unique features, such as hardening in magnetic fields, electromagnetic shielding capability, and directional self-healing capability, while also being reprocessable multiple times and easily recyclable.

Analysis of friction and wear performance of eco-friendly basalt filler reinforced polylactic acid composite using the Taguchi approach

The main goal of this research is to utilize sustainable and eco-friendly basalt materials for the fabrication of bio-based thermoplastic composites. This will help to keep up with ecologically balanced factors. There have been several studies on natural fiber reinforced with different polymer matrices during the past 10 years. As a result, the academics and experts expressed concern about the environmental imbalance. By keeping these points, an attempt was made to fabricate basalt fillers reinforced polylactic acid composites with the maximum weight ratio (30 wt %), and the tribological study is conducted for the fabricated composites. In this study, the Taguchi and analysis of variance (ANOVA) approaches have been used to analyze the coefficient of friction (COF) and specific wear rate (SWR) of polylactic acid composite reinforced with constant 30 wt% basalt fillers. The morphology, particle size, and elemental composition of the basalt fillers are examined using scanning electron microscopy, a particle size distribution analyzer, and energy-dispersive X-ray analysis, respectively. The tribology tests are conducted with Pin-on-Disk Tribometer following the ASTM G99 standard, following the L18 orthogonal array design, which was developed using the statistical program MINITAB-19. The selected parameters for the analysis are basalt (wt %), load (N), speed (rpm), and distance (m) under dry conditions. For PLA samples, the optimum parameters in response to COF is found to be 0 wt% basalt, 3 N load, 100 rpm speed, and 100 m distance; for the SWR output, the optimum parameters are 30 wt% basalt, 6 N load, 100 rpm speed, and 150 m distance. The consistent observation is that adding basalt fillers has not significantly reduced COF but has contributed more to SWR reduction with PLA composite. The best COF value for PLA samples is obtained with low sliding distance. The typical observation across all COF graphs is that the COF value first seems to be lower due to a smoothened polymer surface, rises throughout an experiment, and then stabilizes with very little variance. Regardless of the processing parameters, the depth of wear steadily increases with increasing load as observed in 2D depth profiles. The neat PLA polymer morphology that gives the illusion of deep grooves and many tracks dispersed over a single worn surface shows how the maximum parameter influence is more obvious on the surface of the sample. Overall, the results suggest that thermoplastic composites are feasible for the manufacturing of paper mill rollers.

Mechanically strong, hydrostable, and biodegradable all-biobased transparent wood films with UV-blocking performance

Petroleum-based plastics are useful but they pose a great threat to the environment and human health. It is highly desirable yet challenging to develop sustainable structural materials with excellent mechanical and optical properties for plastic replacement. Here, we report a simple and efficient method to manufacture high-performance all-biobased structural materials from cellulosic wood skeleton (WS) and gelatin via oxidation and densification. Specifically, gelatin was grafted to the oxidized cellulose wood skeletons (DAWS) and then physically crosslinked via Tannic acid (TA), resulting in a significant enhancement of the material properties. Notably, only a mild pressure was applied during the drying process to form a densified TA/Gelatin/transparent wood film(TWF). The developed TA/Gelatin/TWF (thickness:100 ± 12 μm) exhibited a desirable combination of high strength (∼154.59 MPa), light transmittance (86.2 % at 600 nm), low haze (16.7 %), high water stability (wet strength: ∼130.13 MPa) and ultraviolet blocking efficacy which surpass most of the petroleum-based plastics. In addition, due to the all bio-based origins (wood and gelatin), TA/Gelatin/TWF are easily biodegradable under natural conditions, leading to less impact on the environment. These findings would hold promises for exploring high-quality all bio-based wood composites as eco-friendly alternatives to substitute plastics with wide applications, e.g. anti-counterfeiting, UV protection, and flexible electricals.

Poly-Lactic Acid-Bagasse Based Bio-Composite for Additive Manufacturing.

Beer bagasse is a residue waste produced in great amounts; nevertheless, it is still underestimated in the industry. The aim of this paper is to develop an innovative and efficient methodology to recycle the beer bagasse by producing Poly-lactic acid(PLA)-based bio-composites, in the forms of pellets and filaments, to be used in additive manufacturing processes. To assess the suitability of beer bagasse for extrusion-based 3D printing techniques, it was, firstly, physically and chemically characterized. Then, it was added in combination with different kinds of plasticizers to PLA to make bio-composites, analyzing their thermal and physical properties. The results prove the great potential of bagasse, evidencing its printability. Both composites' pellets and filaments were used in two different 3D printing machines and the mechanical properties of the 3D-printed models were evaluated as a function of the composition and the kind of technology used. All the used plasticizers improved processability and the polymer-bagasse interface. Compared to neat PLA, no changes in thermal properties were detected, but a lowering of the mechanical properties of the 3D-printed composites compared to the neat polymers was observed. Finally, a comparison between the efficiency of the two 3D printing techniques to be used with the bio-based composites was performed.

Composite of gum arabic and halloysite as a bio-based acidic catalyst for efficient synthesis of 5-hydroxymthylfurfural

A novel acidic bio-based composite has been synthesized via covalent conjugation of two acidic natural compounds, i.e. halloysite clay mineral and Gum Arabic. Measurement of the acidity of the composite confirmed that its acidity was higher than that of individual components. Halloysite-Gum Arabic composite was successfully applied as a biocompatible catalyst for the dehydration of fructose to 5-hydroxymthylfurfural. The reaction conditions were also optimized via Response Surface Method (RSM) and it was found that using 30 mg catalyst per 0.1 mmol fructose led to 99.2% product yield at 100 °C in 105 min. Gratifyingly, the as-prepared composite was recyclable for seven consecutive runs and only insignificant loss of activity was observed after each run. Notably, the recycled catalyst was structurally and morphologically stable.

Experimental investigation into mechanical performance of novel inorganic-bonded bamboo composite columns under axial compression

Engineering wood and bamboo composites bonded by organic adhesives have gradually become an important component in studies of green and sustainable development in the field of civil engineering. As an alternative solution, studies on inorganic adhesives in bio-based composites have sparked widespread research interest. Herein, a novel bamboo-based composite prepared with an inorganic adhesive was proposed, which is named “inorganic-bonded bamboo composite” and abbreviated as InorgBam. The compressive mechanical property is experimentally investigated. Fifteen groups of columns with various slenderness ratios are tested to evaluate the load–bearing capacity and buckling behavior under axial compressive load. The load–lateral deflection curves and stress–strain curves of the InorgBam columns correlated to the slenderness ratios were obtained. Results show that the strength failure with crushing at the end and buckling failure are the two typical failure modes of the InorgBam column under axial compression. The Euler formula and Newlin–Gahagan approach are adopted for calculating the ultimate stress in cases involving strength failure and buckling failure, and the stability coefficient of the InorgBam columns is analyzed using the prediction methods in the existing codes for the design of timber structures. The stability coefficient calculated by using formulas in the current codes for timber structures is feasible for InorgBam columns, and a proposed formula for the stability coefficient in the present study can be finely applied to the design of InorgBam columns. This study has valuable reference in promoting the structural application of this bamboo-based biomaterials.

Extraction and characterization of novel natural cellulosic fiber from Echinops spinosissimus plant stem

Bio-based composites are outstanding materials to replace many synthetic fiber-based composites due to their biodegradability and sustainable environmental properties. This research aims to characterize and analysis a new cellulosic fibers extracted from Echinops spinosissimus plant stem, to study their integration in the field of various industries such as composites and textiles. Thus, adding and incorporating a new natural fiber to the list of fibers that enter into the production of Bio-based composites materials, and meet the needs of the market that knows a shortage of these materials. In addition, the extracted fibers from Echinops spinosissimus plant, which is abundant and have acceptable properties that can replace the synthetic fibers. The stem anatomy results showed a strong presence of fiber cells, fiber SEM micrographs showed that fiber surface become rough, these fibers have a density of 0.97 ± 0.01 g/cm3, and diameter 280.76 µm. FTIR and XRD showed that these fibers are cellulosic. Thermal analysis revealed that Echinops spinosissimus fiber have a thermal stability of 208°C. Tensile strength, Young modulus and strain at failure were found as 217.54 ± 54.16 MPa, 19.23 ± 0.76 GPa and 3.78 ± 0.36%, respectively. SEM showed that the studied fiber becomes more roughness in the outer surface following the chemical treatments, thus contributing to better adhesion with resin. This work confirmed that Echinops spinosissimus fibers are suitable materials for use in textile and biocomposite applications.

Cross-linked peach gum polysaccharide adhesive by citric acid to produce a fully bio-based wood fiber composite with high strength

As a natural polysaccharide, efficiently converting peach gum (PG) into practical materials remains a significant challenge due to its complex structure and high molecular weight. This study developed a polysaccharide adhesive using PG as the primary raw material and citric acid (CA) as a cross-linking agent to produce a fully bio-based wood fiber composite. The chemical compositions of PG and the synthesis process of PG-CA/55-45 adhesive were mainly discussed. The properties of the composites were explained through a microscopic perspective. The gel permeation chromatography (GPC) analysis revealed that the mean molecular weights of PG and PG-CA/55-45 adhesive were 9.07 × 106 Da and 9.98 × 104 Da, respectively. CA was introduced to depolymerize PG and cross-linked the degraded PG to form macromolecules with higher strength by the esterification reaction. PG-CA/55-45 adhesive demonstrated good mildew resistance and thermal stability. In addition, the composites exhibited excellent mechanical properties and water resistance. This study provided a simple and feasible approach to developing a polysaccharide adhesive for producing higher strength wood fiber composites, which can propose a new strategy for realizing the high-value utilization of PG.

Sustainable epoxy composites with high thermal conductivity using poly(lipoic acid) modified liquid metal as crosslinkers

With the increasing demand for electronics integration and the increasing accumulation of e-waste, thermal management materials combing high conductivity and sustainability is highly desired. Herein, bio-based recyclable epoxy composites with significantly improved thermal conductivity were prepared by utilizing poly(lipoic acid) modified liquid metal (LM) as the crosslinkers. The strong interactions between poly(lipoic acid) and LM enable the formation of a poly(lipoic acid) shell layer coating on the LM droplet core, which facilitates the dispersion of LM droplets as well as interfacial thermal transport in the composites. As a result, the composite with only 25 vol% LM exhibits a thermal conductivity of 0.82 W/(m·K), which is higher than those of the previous studies with randomly filled LM at the same loading. In addition, attributed to the existence of dual dynamic bonds (disulfide bonds and β-hydroxyl ester bonds), the composites are reprocessable and their thermal conductivities are maintained after reprocessing. Moreover, the composites can be degraded under mild reducing conditions. This work presents a novel approach for the preparation of high-performance thermal management materials featuring recyclability and degradability.

Enhancing Sustainability: Jute Fiber-Reinforced Bio-Based Sandwich Composites for Use in Battery Boxes.

The rising industrial demand for environmentally friendly and sustainable materials has shifted the attention from synthetic to natural fibers. Natural fibers provide advantages like affordability, lightweight nature, and renewability. Jute fibers' substantial production potential and cost-efficiency have propelled current research in this field. In this study, the mechanical behavior (tensile, flexural, and interlaminar shear properties) of plasma-treated jute composite laminates and the flexural behavior of jute fabric-reinforced sandwich composites were investigated. Non-woven mat fiber (MFC), jute fiber (JFC), dried jute fiber (DJFC), and plasma-treated jute fiber (TJFC) composite laminates, as well as sandwich composites consisting of jute fabric bio-based unsaturated polyester (UPE) composite as facing material and polyethylene terephthalate (PET70 and PET100) and polyvinyl chloride (PVC) as core materials were fabricated to compare their functional properties. Plasma treatment of jute composite laminate had a positive effect on some of the mechanical properties, which led to an improvement in Young's modulus (7.17 GPa) and tensile strength (53.61 MPa) of 14% and 8.5%, respectively, as well as, in flexural strength (93.71 MPa) and flexural modulus (5.20 GPa) of 24% and 35%, respectively, compared to those of JFC. In addition, the results demonstrated that the flexural properties of jute sandwich composites can be significantly enhanced by incorporating PET100 foams as core materials.

Mechanical Properties of Bio-Based Sandwich Composites Containing Recycled Polymer Textiles.

In this paper, sandwich composites were produced by compression moulding techniques, and they consisted of regenerated cellulose fabric (rayon) and bio-based polypropylene (PP) to form facings, while virgin and recycled polyamide (PA) textiles were used as core materials. To compare the mechanical performance between sandwich composites and typical composite designs, a control composite was produced to deliver the same weight and fiber mass fraction from rayon and PP. To evaluate the influence of recycled textile on the mechanical properties of the composites, a series of flexural, low velocity impact (LVI) and tensile tests were performed. It was found that the incorporation of thicker PA textile enhanced the bending stiffness by two times and the peak flexural force by 70% as compared to those of control. Substitution of a layer of recycled textile for two layers of rayon provided a good level of impact energy absorption capacity (~28 J) and maximum force (~4893-5229 N). The tensile strength of the four sandwich composites was reported to be in the range of 34.20 MPa and 46.80 MPa. This value was 91.90 for the control composite. The 2D cross-section slices of the composite specimens did not show any evidence of fiber tow debonding, fiber bundle splitting, or delamination.

A fluorescent biomass derived cellulose/PANI/NiFe2O4 composite for the mitigation of toxic pollutants and Cr(VI) sensing from aqueous environment

Targeting routine water pollution due to industries and biowaste management, present work focuses on synthesis of biomass derived photocatalysts for abatement and detection of noxious pollutants. Herein, a series of nickel ferrite/cellulose-polyaniline composites (NF/C-PA) were fabricated via hydrothermal route and were successfully characterized. The comparative analysis of all the synthesized composites was carried out for photo-Fenton degradation of different pollutants, namely, Remazol brilliant yellow (RBY), Safranin O (SO) dyes, Levofloxacin (LVX) and Ofloxacin (OFX) drugs, and para-nitrophenol (PNP). Amongst all composites, NF/C-PA 1.5 bestowed best photocatalytic results with a degradation value of 95.42 % (k1 = 0.0859 min−1), 93.42 % (k1 = 0.0859 min−1), 91.96 % (k1 = 0.0731 min−1), 87.44 % (k1 = 0.1213 min−1), and 90.73 % (k1 = 0.1195 min−1) within 30 min for RBY, SO, LVX, OFX and PNP, respectively. Furthermore, the synthesized NF/C-PA 1.5 composite was successfully employed as fluorescence probe for selective and sensitive detection of Cr(VI) in wastewater with the limit of detection value 4 µM in the linear range of 0 to 200 µM. The sensor demonstrated virtuous pertinency in real water samples. Thus, the synthesized biobased composites exhibited multifunctional platform for the removal and detection of pernicious contaminants from aqueous environment.

Water aging effects on the flexural properties of fully biobased coir fiber composites

AbstractThis work describes the flexural behavior of biocomposites composed of a polyurethane matrix derived from castor oil plants and coir fibers. A statistical design is performed to identify the effects of fiber alkaline treatment and aging on the flexural modulus and strength of the composites. Physical tests and failure analyses are carried out to better assess their mechanical performance. A second experiment at 100% relative humidity is performed on treated fiber composites to compare with those obtained by immersion in water. The flexural modulus of the composites is not significantly affected by the fiber alkali treatment, while the strength is reduced by 35.17% when treated fibers are considered. Increasing the exposure time of composites under both aging conditions progressively reduces their flexural properties. The aging process of biocomposites in an environment with 100% relative humidity takes twice as long to reduce to the same flexural properties as those aged in water.Highlights Composites made with treated fibers showed higher apparent density and lower porosity. Water aging reduces flexural modulus and strength of biobased coir composites. The bending properties are strongly dominated by the properties of biobased polymer. 100% relative humidity takes twice as long to reduce to the flexural properties as those aged in water. Untreated coir fibers achieve superior bending properties under moisture aging.