Wood Fiber Composites Research Articles

Innovative Approaches for Manufacturing Epoxy-Modified Wood and Cellulose Fiber Composites: A Comparison between Injection Molding and 3D Printing.

The current study focused on improving the properties of polylactic acid (PLA) for wider application in load-bearing scenarios. Various methods were explored to optimize the interaction between PLA and natural fibers, particularly wood fibers (WFs). Alkalized and epoxy-impregnated WFs were evaluated against untreated WFs and cellulose fibers in both injection molding (IM) and fused deposition modeling (FDM). FTIR analysis revealed the removal of hemicellulose and lignin in alkalized WFs and uniform epoxy curing. Addition of fibers reduced PLA's thermal stability while acting as nucleating agents. Additionally, fibers augmented the storage modulus of biocomposites, with alkalized fibers exhibiting the highest tensile modulus in IM. FDM samples with a 0° raster angle showed superior impact resistance compared to IM counterparts. Moreover, raster angle significantly influenced FDM biocomposite properties, enhancing the tensile strength and modulus of untreated WF and cellulose fibers at 0°. Although FDM did not produce alkalized WF samples, epoxy impregnation emerged as a promising method for enhancing PLA/WF composite mechanical properties in the IM process, offering valuable insights for composite material development.

In situ pretreatment of wood samples with deep eutectic solvents for enhanced lignin removal and enzymatic Saccharification efficiency optimization

Deep eutectic solvents (DESs) are commonly utilized as an effective pretreatment method for biomass materials, particularly for enhancing the value of lignocellulosic biomass. However, to the best of our knowledge, the utilization of DESs for in situ pretreatment of wood samples has been seldom reported. In this study, the ability of five DESs systems to in-situ pretreatment of balsa wood samples was investigated. Among of them, the Choline Chloride-Ethylene Glycol-P-Toluenesulfonic Acid (ChCl-EG-PTSA) system showing an excellent lignin removal rate (the lignin removal of 87.34 % and cellulose retention of 86.32 %), which is significantly better than the delignification effect of the traditional acid chlorite method (lignin removal of 72,13 % and cellulose retention of 64.57 %). In addition, in the subsequent enzymatic saccharification experiments, after the wood samples were pretreated in situ by the ChCl-EG-PTSA system, the enzymatic saccharification yield of cellulose reached 75.46 %, and the enzymatic saccharification yield of xylose reached 92 %. At the same time, this study also used SEM, FTIR, XPS, TGA and other testing technologies to conduct detailed analysis and characterization of the pretreated samples. This comprehensive analysis unequivocally demonstrated the viability of the ChCl-EG-PTSA system as an environmentally sustainable and efficient approach for pretreating forest biomass. Significantly, this in-situ wood pretreatment strategy significantly lays a robust research groundwork for the development of multifunctional wood fiber composites in subsequent stages.

Configuring single-layer MXene nanosheet onto natural wood fiber via C–Ti–C covalent bonds for high-stability Li-S batteries

Lithium-sulfur batteries (LSBs) are considered promising candidates for next-generation battery technologies owing to their outstanding theoretical energy density and cost-effectiveness. However, the low conductivity and polysulfide shuttling effect of S cathodes severely hamper the practical performance of LSBs. Herein, in situ-generated single layer MXene nanosheet/hierarchical porous carbonized wood fiber (MX/PCWF) composites are prepared via a nonhazardous eutectic activation strategy coupled with pyrolysis-induced gas diffusion. The unique architecture, wherein single layer MXene nanosheets are constructed on carbonized wood fiber walls, ensures rapid polysulfide conversion and continuous electron transfer for redox reactions. The C–Ti–C bonds formed between MXene and PCWF can considerably expedite the conversion of polysulfides, effectively suppressing the shuttle effect. An impressive capacity of 1301.1 mA h g−1 at 0.5 C accompanied by remarkable stability is attained with the MX/PCWF host, as evidenced by the capacity maintenance of 722.6 mA h g−1 after 500 cycles. Notably, the MX/PCWF/S cathode can still deliver a high capacity of 886.8 mA h g−1 at a high S loading of 5.6 mg cm−2. The construction of two-dimensional MXenes on natural wood fiber walls offers a competitive edge over S-based cathode materials and demonstrates a novel strategy for developing high-performance batteries.

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.

Preparation of biomass composites with high performance and carbon sequestration from waste wood fibers

Forest ecosystems play a significant role in mitigating global warming, primarily because wood is recognized as a crucial natural material for capturing carbon. However, the increasing global demand for wood conflicts with the idea of sustainable carbon capture, emphasizing the importance of recycling waste wood and utilizing it in multiple ways. Despite the potential of wood fibers to strengthen composites, the complexity of their preparation and their natural sugar content limit their applications in recycling waste wood. This study combines the Random Forest and NSGA II algorithms for comprehensive multi-objective optimization, focusing on enhancing the strength, resilience, and carbon capture capabilities of composites. In-depth microstructural analyses, along with elemental mapping, clarify how wood fibers contribute to toughening and resistance to cracking, affirming their vital role in improving the mechanical properties of composites. The study determined the optimal mixing ratio and mechanism of action of NaOH and CH3COOH treatments. The Pareto solution set derived from the algorithm aids intricate multi-objective balance analyses. Notably, discrepancies between experimental and optimized values remain minimal, and were recorded at 1.03%, 0.85%, 1.76%, and 2.31%, respectively, thus reinforcing model precision and trustworthiness. Cementitious wood fiber composites' merits set the stage for sustainable product innovations, transitioning theoretical insights into eco-conscious practical applications.

Additive manufactured acoustic absorbers made of wood-fiber composites with modified infill patterns

ABSTRACT The rapid urbanization and economic expansion have increased the negative consequences of environmental noise pollution. The sound that originates from various sources comes from distinct spectrums. To address the aforementioned issue, acoustic absorbers were 3D printed with varying infill patterns to absorb sound across a wide range of frequencies. Acoustic absorbers made of polylactic acid/polyhydroxyalkanoates-wood fibers (PLA/PHA-WF) were fabricated using Fused Deposition Modelling (FDM) technology, and their physical, mechanical, water absorption, biodegradation, and acoustic characteristics were measured and discussed. Acoustic absorbers printed with different infill patterns have a slight difference in density due to the size of the pores and the contact sites exhibited by the infill pattern. As a result, acoustic absorbers printed with varying infill patterns allow sound waves to enter and absorb sound at distinct spectrum levels. Modifying the infill pattern also had an effect on mechanical, water absorption, and biodegradation properties with minor deviations. The proposed biodegradable acoustic absorbers made of natural fiber composites and manufactured by FDM can be installed on building walls or roofs depending on the required acoustic absorption spectrum.

Synergic effect of basalt/wood fiber reinforced polylactic acid hybrid biocomposites against fungal decay

In addition to the traditional fibre-reinforced composites, the investigation of novel composites with significant potential for engineering applications attracts increasing attention. In this study, the decay resistance of basalt and/or wood fibre-reinforced polylactic acid (PLA) biocomposites was evaluated with a soil block test by using white rot fungi, Trametes versicolor (Trv) and Irpex lacteus (Irl), and brown rot fungi, Poria placenta (Pop) and Gloeophyllum trabeum (Glt), and a soft rot fungus, Chaetomium globosum (Chg) after 8 weeks of water submersion. Water absorption rate during the water submission and weight losses after the decay test were determined. Furthermore, decay in biocomposites was characterized by SEM and ATR-FTIR. Results showed that the water absorption increased between 52.4–67.5% for wood fibre composites when compared to basalt fibre-reinforced biocomposites. PLA showed good decay resistance against all fungi attacks. However, as the ratio of basalt and wood fibre in the hybrid biocomposites increased, the fungi resistance decreased. The lowest weight loss, 4.9% was found in the biocomposites containing the highest percentage of basalt fibre. On the other hand, the highest weight loss, 54.2% was observed in the composites containing the highest percentage of wood fibre. The results clearly showed that the hybridization of basalt and wood fibres improves the decay resistance of the biocomposites compared to only wood fibre-reinforced composites. However, as the percentage of wood increased in the composites, the decay resistance decreased. SEM and FTIR analysis confirmed the degradation and revealed the degradation mechanism.

Mechanical behavior of all-lignocellulose composites—Comparing micro- and nanoscale fibers using strain field data and FEM updating

Hot-pressed, binder-free wood fiber (WF) composites can serve as load-bearing and eco-friendly materials, and the comparison of nanoscale fibril reinforcement with microscale wood fibers is of interest. We investigated property differences and interpreted deformation mechanisms with strain field measurements using digital image correlation combined with orthotropic, elastic–plastic finite element model updating predictions. Random-in-plane microfibrillated lignocellulose (MFLC) composites showed better mechanical properties than WF composites due to stronger strain-hardening from lower porosity and better interfibrillar adhesion, provided by the intrinsic lignin-hemicellulose binder. Axially oriented wood fiber composites (O-WF) achieved comparable mechanical properties to random MFLC, with lower values for eco-indicators. The FEM updating method could successfully determine all 4 independent elastic constants from one 45° off-axis experiment, although the plasticity model required two more experiments.

Dynamical mechanical behaviors of rubber-filled wood fiber composites with urea formaldehyde resin

Wood composites glued with thermosetting synthetic resins tend to show inadequate damping performance caused by the cured resinous matrix. Waste rubber maintains prominent elasticity and is feasible to be an optional modifier. To that end, composite panels of granulated tire rubber (GTR) powders and thermal-mechanically pulped wood fibers were fabricated in this study. Urea formaldehyde (UF) resin was applied as the bonding agent (10% based on wood/rubber total weight). Dynamical mechanical analysis (DMA) was conducted to disclose the thermo-mechanical behaviors of the rubber-filled wood fiber composites. Influence of two technical parameters, i.e., GTR powder size (0.55–1.09 mm) and addition content (10%, 20% and 30% based on wood/rubber total weight), was specifically discussed. The results showed that storage modulus (E') of the rubber-filled composite decreased while loss factor (tan δ) increased monotonously along with elevated temperature. A steady “plateau” region among 110–170 °C was found where both E' and tan δ keep constant. Accordingly, tan δ showed two peak values at 103–108 and 231–233 °C due to glass transition of lignin and thermal degradation of hemicellulose, respectively. Addition of rubber fillers resulted in lower bending and internal bonding strengths as well as storage modulus values. When the temperature was above 183 °C, all the rubber-filled composites showed higher tan δ values than the control. The findings above fully demonstrate the improved damping performance of the UF-bonded wood fiber composites on account of rubber component. Further work is still needed to optimize the rubber/fiber interfacial bonding strength.

Investigation of the effect of graphene nanosheets on the properties of beech/polylactic acid flour composites

In this study, the effect of different amounts of graphene on the physical and mechanical properties of polylactic acid beech wood fiber composites were investigated. Beech flour and graphene were used as reinforcing phases with different weight percentages (0, 0.5, 1.5 and 2.5%). Samples were prepared by solution method and after pressing, mechanical properties such as flexural strength, flexural modulus, impact resistance and tensile strength and physical properties including differential scanning calorimetry test (DSC) and X-ray scattering test were measured. The results of analysis of variance showed that the effect of treatment was significant for flexural strength ( p < .05) and flexural modulus, impact resistance and tensile strength ( p < .01). The highest flexural strength, flexural modulus and tensile strength were related to treatment 8, which included 30% beech flour, 67.5% polylactic acid and 2.5% graphene, and the highest impact resistance was related to treatment 2, which included 20%. The weight of beech flour was 79.5% by weight of polylactic acid and 0.5% by weight of graphene, which were significantly different from other treatments ( p < .05). Based on the DSC, the melting temperature of the polymer matrix was transferred to higher temperatures by adding graphene nanosheets. The results of X-ray diffraction test showed that for all three treatments there is a similar trend in terms of peak graph and with increasing the concentration of graphene nanoparticles, only the peak intensity changed. It can be said that the addition of nanographene to beech-polylactic acid flour composites has improved the mechanical and physical properties.

Effect of Thickness and Infill Density on Acoustic Performance of 3D Printed Panels made of Natural Fiber Reinforced Composites

ABSTRACT Additive manufacturing (AM) of Natural Fiber-Reinforced Composites through Fused Deposition Modeling is receiving much attention in recent years. AM is very appealing for complex shape structures that can be inconvenient to produce by other methods. In this study, the acoustic panel made from polylactic acid reinforced with wood fiber composite was 3D printed by varying its thickness and infill density. The sound absorption coefficient was measured using an impedance tube. The thin panel with back air gap was found to absorb sound at mid-frequency range resembling the Helmholtz resonator. The absorption performance for the thick panel can be controlled by controlling the infill density of the panel. Customizing the acoustic absorption is therefore possible for panels from biodegradable materials by AM.

Study on the structure and properties of poly(3-hydroxybutyrate-co-4-hydroxybutyrate)/ rubber wood fiber composites modified with titanate coupling agent

Study on the structure and properties of poly(3-hydroxybutyrate-co-4-hydroxybutyrate)/ rubber wood fiber composites modified with titanate coupling agent

The researches concern the influence of the helix angle on the composite machining process

Magnesium oxide-reinforced wood fiber composites (MgO/WF) are a new type of multifunctional material, which can be used in different occasions, such as shopping malls, hotels, and residential buildings. Referring to the relevant literature, there is no research on the milling performance of MgO/WF. In order to better understand the relevant knowledge of the processability of MgO/WF, three cutters with different helix angles were used in this experiment to carry out the cutting of MgO/WF, and the variation trend of its cutting force, tool wear, and surface roughness was measured. The results are as follows: First, under the same cutting parameters, the resultant force decreases with the increase of helix angle. Second, with the increase of helix angle, the tool wear was slightly improved. Third, the surface roughness (Ra) showed an increasing trend with the decrease of helix angle. In the end, when milling MgO/WF, better machined surface quality and less tool wear can be obtained by selecting the tool with larger helix angle.

Mixed-culture polyhydroxyalkanoate (PHA) production integrated into a food-industry effluent biological treatment: A pilot-scale evaluation

Production of a mixed microbial culture (MMC) biomass for polyhydroxyalkanoate (PHA) production was integrated into the wastewater treatment (WWT) of a potato-starch factory. A pilot-scale on-site evaluation was conducted over ten months, with inherent water quality variations including organic composition, temperature, and pH. The wastewater was rich in acetate and the organic matter content fluctuated from 50 to 90 % with respect to volatile fatty acids (VFAs). The PHA accumulation potential (PAP) of the surplus biomass, nevertheless, remained from 0.40 to 0.70 gPHA/gVSS. Biomass PAP characteristics were benchmarked at both pilot and laboratory scales using different feedstocks and accumulation methods. The resultant co-polymer type could be readily shifted by changes in feedstock VFA content. Selected polymer batches were recovered at pilot scale as commercial-quality prototype materials for development of PHA-based wood-fibre composites. WWT performance with 98 % organic contaminant removal remained consistent throughout. The good settleability of the pilot-scale biomass was in contrast to the poorly settleable biomass from the factory’s full-scale activated sludge. Metered nitrogen and phosphorus addition ensured stable WWT without major nitrification levels. Successful robust outcomes of both feast-famine selection principles and WWT can be translated and integrated into the full-scale WWT by a proposed adaptation to existing infrastructure. Analogous aerobic feast enrichment is proposed to be achievable with continuous or intermittent flow through a process selector/zone. This pilot-scale experience under actual field conditions of industrial WWT provides further evidence for the technical viability to produce biomass for PHA production while maintaining standards in effluent water quality.

Characterization of Wood and Graphene Nanoplatelets (GNPs) Reinforced Polymer Composites.

This paper investigates the utilization of commercial masterbatches of graphene nanoplatelets to improve the properties of neat polymer and wood fiber composites manufactured by conventional processing methods. The effect of aspect ratio of the graphene platelets (represented by the different number of layers in the nanoplatelet) on the properties of high-density polyethylene (HDPE) is discussed. The composites were characterized for their mechanical properties (tensile, flexural, impact) and physical characteristics (morphology, crystallization, and thermal stability). The effect of the addition of nanoplatelets on the thermal conductivity and diffusivity of the reinforced polymer with different contents of reinforcement was also investigated. In general, the mechanical performance of the polymer was enhanced at the presence of either of the reinforcements (graphene or wood fiber). The improvement in mechanical properties of the nanocomposite was notable considering that no compatibilizer was used in the manufacturing. The use of a masterbatch can promote utilization of nano-modified polymer composites on an industrial scale without modification of the currently employed processing methods and facilities.

The environmental attributes of wood fiber composites with bio-based or petroleum-based plastics

While bio-based composites (bio-based plastics reinforced with natural fibers) have been discussed as potential sustainable alternatives to petroleum-based plastic composites, there are few quantitative environmental impact assessments of these materials. This work presents comparisons of petroleum-based and bio-based plastics as well as their composites to (1) assess environmental impacts from plastics and composite production and (2) determine which environmental impacts can be mitigated through production of bio-based composites, based on current manufacturing methods. Environmental impact assessments were performed to determine the burdens associated with cradle-to-gate production of bio-based and petroleum-based plastics and their composites with wood flour (i.e., sawdust) filler. The scope of this work incorporated emissions from thermoplastic and wood flour production as well as pelletization, molding, and transportation processes. Environmental impacts were assessed for several impact categories using the US Environmental Protection Agency’s TRACI method. Using impacts quantified, as well as material property data from 36 sources in the literature, comparisons were drawn between composite types. Multiple functional units were used including a constant mass of material produced and two comparison methods normalizing environmental impacts by material properties. Uncertainty assessments were performed to determine environmental impact distributions for each plastic and wood fiber composite type. The production of bio-based plastics and their composites led to lower environmental impacts than petroleum-based plastics and composites in several impact categories: global warming potential, fossil fuel depletion, and certain human health impacts. However, the production of bio-based plastics and their composites also resulted in some higher environmental impacts, such as eutrophication. Bio-based composites are capable of possessing similar or improved mechanical properties to their petroleum-based counterparts. As such, normalized environmental impacts to material properties indicated that bio-based composites could lead to desirable combined mechanical and environmental attributes for certain applications. Considering the differences between environmental impact categories and uncertainties in environmental impact assessments, selection of constituents cannot be based solely on material feedstock to mitigate environmental impacts in wood fiber composites. Findings indicate that both environmental impact assessments and mechanical properties should be considered concurrently to effectively distinguish the benefits of selecting petroleum-based or bio-based plastics. This work shows that depending on the intended application, the selection of a bio-based feedstock could either be beneficial for mitigating certain environmental impacts, have little effect on impacts, or increase environmental impacts. These findings reveal the importance of considering property alteration and multiple effects of utilizing these resources.

Regenerated waste tire powders as fillers for wood fiber composites

Waste rubber retains good elasticity and can be regenerated for use in special applications. In this research, wood fiber composites were made with waste tire powders (WTPs) as functional fillers. The physical-mechanical properties of the wood-rubber composite (WRC) panels, i.e., inner bond (IB) strength, static bending modulus (MOE), strength (MOR), and thickness swelling (TS) were assessed. The surface micro-morphology of the WRC panels was quantitatively analyzed and was graphically simulated with Matlab software. The results showed that WTPs decreased the mechanical strength and modulus of the hybrid composites, which was caused by the weak fiber/WTP interfacial adhesion. The addition of WTPs roughened the surface of composite panels. However, WRC panels showed improved hygroscopic stability and flexibility compared to pure wood fiber composites. Sanding can flatten the rougher WRC panel surface; however, it brings tiny pits to the surface that are caused by loss of rubber powders. Surface overlaying with resin impregnated paper was found to be effective to cover the tiny pits. This study showed that it is feasible to make value added rubber filled wood fiber composites with satisfactory performance.

The Analysis of Size and Arrangement Effects of Petung Bamboo Split Fiber to the Matrix Interface Bond with Laminated Bamboo Split Fiber as Construction Materials for Wooden Vessels

Bamboo is an extraordinary natural material. Bamboo can grow quickly, is cheap and widely available. The material property is light but harder and stronger than wood or glass fiber composites. The purpose of this study was to determine the effect ofarrangement and size of petung bamboo split fiber to the matrix interface bond of laminated bamboo split fiber. The benefits of this study can contribute knowledge and innovation to the development of science in the field of vessel material technology in education field, especially in the field of shipping. This research was carried out by compressive test, tensile test, and shear test to the matrix interface bond of laminated bamboo and petung bamboosplit fiber with the tangential and radial test directions (x, y, and z axis) using the ASTM D143 standard.After testing, it can be concluded that the tensile strength and compressive strength of the brick arrangement is better, while for the shear strength, it is better in the parallel arrangement, furthermore the thicker the bamboo split size, the greater the stress value. The average results obtained for tensile test is 44 kg/cm2, the shear test is 38,5 kg/cm2, and the compressive test is 341,05 kg/cm2. The average compressive strength of these results can be classified into Strong Class III on BKI (Indonesian Classification Bureau) of Wooden Ships. The direction of the best tensile strength test is on the Y axis, the direction of the best shear strength test is on the Z axis, and the direction of the best compressive strength is on the X axis. The higher the glue Interface value for each cm2, the greater the interface bond strength due to the need of glue in mm/cm2 is higher, on the contrary the lower the glue Interface value in each cm2, the lower the interface bond strength due to the need of glue in mm/cm2 is lower.

The influence of double-layered distribution of fire retardants on the fire retardancy and mechanical properties of wood fiber polypropylene composites

Expandable graphite (EG) and ammonium polyphosphate (APP) distributed in different layer of wood fiber and polypropylene composites (WPPC) were prepared. The results of cone calorimetry showed that the layered distribution of EG and APP considerably improved the fire retardancy of the overall composites, and the char residue rate was 41.9%, which increased by 200% compared with that of single-layered WPPC. Moreover, a more firm and compact physical structure char in the base layer formed due to protection of EG in the surface layer. The flexural strength and modulus of double-layered WPPC also increased compared with these of the single-layered WPPC with EG.

Characteristics of aging of wood-fiberboard from the position of IR spectroscopy

Fiber boards, like other wood-polymer composites, are widely used in construction. However, their service life is often less than that declared by the manufacturer, which is due to insufficient knowledge of the processes of degradation of polymer components of resin and wood filler under the influence of aggressive environmental factors. In this regard, the task is to reveal, using reflective IR spectroscopy, structural changes in the molecular structure of polymeric substances included in a wood fiber composite after heat aging, artificial UV radiation and exposure to direct sunlight. The results of the study showed that the IR spectra of all samples are identical, but differ in the intensity of individual absorption bands. This suggests that under the influence of aging factors, a free-radical rupture of hydrogen, hydrocarbon and ether bonds occurs in various functional groups of cellulose, hemicellulose, lignin and resin. At the same time, heat aging causes structural changes throughout the entire volume of the slab, and artificial UV irradiation destroys the surface layer about one millimeter thick. Sunlight during the summer season destroys the surface layer less than 0.5 mm thick and contributes to additional structuring of the polymer components of the resin and wood of the inner layers as a result of heating the board.