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Modified wood ceramic is a carbon-carbon composite material obtained by calcining pine wood in a nitrogen atmosphere by using montmorillonite and magnesium chloride as modifiers. The Plackett–Burman fractional factorial design was used to analyze 11 parameters in the experimental preparation of modified wood ceramics and to determine the factors that significantly affected the ammonia-nitrogen adsorption capacity and apparent porosity of the modified wood ceramics while optimizing the composite properties of the modified wood ceramics. Experimental results of the Plackett–Burman fractional factorial design showed that the filling weight, the mass ratio of wood fiber to wood powder, the mass ratio of montmorillonite to anhydrous ethanol, and the heating rate significantly influenced the comprehensive performance of the modified wood ceramics. The structure and properties of the modified wood ceramics were determined using scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and the Brunauer–Emmett–Teller (BET) method. For ammonia nitrogen as the target pollutant (initial concentration: 100 mg/L), results of isotherm model fitting showed that the Freundlich isotherm model parameter fitted the adsorption process of ammonia nitrogen well. The results show that the pseudo-second-order model was better fitted to describe the experimental data than the pseudo-first-order kinetic, intraparticle diffusion, Elovich, and double–constant models. The filling weight, the mass ratio of wood fiber to wood powder, the mass ratio of montmorillonite to anhydrous ethanol, and the heating rate had a stronger impact on the comprehensive performance of the modified wood ceramics. [Display omitted] [ABSTRACT FROM AUTHOR]

In order to alleviate environmental pollution and the shortage of petroleum resources, improve the utilization of renewable materials, the research of biodegradable green composite materials has become a research hotspot. In this paper, Poplar Wood powder(PWP) and Polylactic acid(PLA) were selected, adding poly lactic acid graft maleic anhydride (MPLA) and Silane co upling agent KH-550 (KH550) as a compatibilizer and coupling agent to improve interface compatibility, at the same time, poly Butylenedioate- co -terephthalate (PBAT) and poly Butylene Succinate (PBS) were added to improve the toughness of the composites. The experimental results show that, the impact strength of 20 %-KMPP/PBAT/PBS composite modified by MPLA and KH550 was 20.70 kJ/m−2. Secondly, the hydrophobic angle of the composite material is as high as 112°. It is found that the high content of PWP with small particle size (200 mesh) can make it more evenly dispersed in the composite material, and the cross section of the composite material was smooth. The modified composite was 4.24$/kg, which reduced the cost by 28.07 %. The research results have opened up a new way to develop 3D printed biomass composites with low cost, high compatibility, high toughness and good environmental adaptability, and broadened the application scope and value of the composites. [Display omitted] • The 3D printing biomass composites with high strength and toughness were prepared by melt extrusion method. • It has good interface compatibility. • It has low cost, high compatibility, high toughness and good environmental adaptability. [ABSTRACT FROM AUTHOR]

This paper describes a statistical and mathematical approach to optimize the mechanical properties of a wood plastic composite with Polyethylene Terephthalate (PET) as polymeric matrix. Wood plastic composite are materials that consist of a primary continuous polymer phase, where a secondary filler dispersed phase is embedded, the filler generally is wood fibers or sawdust. The slack variable approach in mixture experiments, consist in selecting a component of the mixture as slack variable, to subsequently design and analyze the experiment in terms of the remaining components. With the experimental design information three slack variable model were fit. Using response surface graphs, we show how different compositions modify the mechanical properties of wood plastic composite. Besides, by the desirability function, the optimal formulation of the compound that simultaneously maximizing the mechanical properties of wood plastic composite, was obtained. Finally, the components proportions that provides the best tensile, flexural and compression strength are presented. [ABSTRACT FROM AUTHOR]

Wood derived carbon has been developed as promising host material for anchoring CoP@CoFe particles towards efficient OER application, which demonstrates widespread paradigm for constructing renewable and affordable hybrid materials for electrochemical energy storage and conversion. [Display omitted] • Natural wood derived carbon supported shell-core CoP@CoFe is designed for OER. • CoP@CoFe decorated on CW channels supplies large numbers of catalysis sites. • Integrating CoP@CoFe with CW supplies enhanced charge and mass flow. • Shell-core structure with interface effect improves intrinsic OER efficiency. • CoP@CoFe/CW exhibits overwhelming OER performance in alkaline media. Development of hybrid materials with specific architecture, interface, and multicomponent interactions demonstrates effective paradigm for pursuing high-performance energy conversion materials. Herein, using renewable and inexpensive wood-derived carbon as host, the shell-core CoP@CoFe particles are embedded on walls of carbonized wood channels (termed as CoP@CoFe/CW) to fabricate composite catalyst for electrocatalysis oxygen evolution reaction (OER). With benefits of the well distribution of CoP@CoFe particles, high conductivity of CW with channels, and good integration between them, highly exposed catalysis surface as well as rapid charge/mass transfer are achieved. The interface effect of shell-core hybrid activates the intrinsic OER efficiency of CoP@CoFe. Thus, the designed CoP@CoFe/CW yields excellent OER performance with ultralow overpotential of 120 mV (10 mA cm−2). This strategy of catalyst design based on eco-friendliness and renewable CW host may offer promising reference to explore composite materials with high conductivity and fast mass transfer for water electrolysis and other energy storage/conversion systems. [ABSTRACT FROM AUTHOR]

Polyaniline (PANI) electrode materials exhibit low capacitance and poor stability due to self-shrinkage and agglomeration in practical applications. In this work, PANI was grown in situ on the framework of the liquefied wood carbon aerogel (LWCA) skeleton by chemical oxidation polymerization to improve the self-agglutination problem of PANI, obtaining the composite electrode material (LWCA-PANI) for hybrid supercapacitors. As expected, Three-dimensional structure of LWCA could effectively hinder the aggregation of polyaniline nanofibers, significantly expanding the accessible area of ions and alleviating volume expansion by preventing stacking to improve capacitive performance. The optimized LWCA-PANI3 electrode material exhibited a remarkable specific capacitance of 507.55 F g−1 at a current density of 0.5 A g−1, and demonstrated excellent cycle stability with a retention rate of 75.37% after 4000 cycles. Furthermore, the supercapacitor assembled by LWCA-PANI3 demonstrated a largest energy density of 32.08 W h kg−1 at 400 W kg−1 power density and an admirable cycling durability of 76.12% retention for up to 4000 cycles. Consequently, LWCA-PANI3 composites showed a broad application prospect in electrode materials for hybrid supercapacitors. [Display omitted] • Polyaniline (PANI) was successfully grown on liquefied wood carbon aerogel (LWCA). • LWCA prevented PANI agglomeration to improve the electrochemical performance. • LWCA-PANI symmetric supercapacitor's energy density was 32.08 W h kg−1. • LWCA-PANI electrodes had high specific capacitance and good cycle stability. [ABSTRACT FROM AUTHOR]

Wood, with high carbon contents and abundant vertically oriented channels, has unique advantages in preparing high mass-loading carbon-based freestanding supercapacitor electrodes. However, there is considerable room for enhancing the capacitive performance of wood-derived carbon electrodes. A one-step chemical vapor deposition (CVD) method mediated by dicyandiamide using iron-based nanoparticles as catalysts was proposed to enhance the utilization of vertical channels in wood-based carbon electrodes and improve their pore structure and chemical composition. This approach aimed to fabricate composite electrodes with enhanced mass loading, interwoven conductive carbon nanotube networks, well-developed hierarchical porous structure, and abundant nitrogen/oxygen-containing functional groups. The effect of CVD temperature on the physical/chemical properties and capacitance performance of the composite material was investigated. Consequently, the optimal electrode (CW/NCNTs-800) attained a competitive initial specific capacitance of 5762 mF cm−2 at 5 mA cm−2 and demonstrated a satisfactory rate performance with the specific capacitance of 3520 mF cm−2 at 300 mA cm−2. In addition, the durable electrode demonstrated commendable cycle stability, maintaining a capacitance retention of 93 % through 30,000 cycles at 30 mA cm−2. This study on wood-derived high mass-loading supercapacitor electrodes can provide a novel perspective on the application of high-performance energy storage devices. [Display omitted] [ABSTRACT FROM AUTHOR]

Wood has excellent properties such as biodegradability, high reactivity and rich channel skeleton structure. However, the defects such as hole blockage and limited specific surface area limit the application of wood-based materials in wastewater treatment. Therefore, in this research, wood substrates (DTWS) were treated using a deep eutectic solvent method, which was able to remove both lignin and hemicellulose from wood. Wood-based carriers with high specific surface area and high chemical activity were formed. The DTWS-Ag material was formed by growing Ag nanoparticles (NPs) in wood channels by hydrothermal method. The results showed that with the increase of lignin and hemicellulose removal, the degradation performance of DTWS-Ag material showed a volcanic trend due to the interaction between Ag and the inner wall of the pipe. The pore size and the amount of Ag NPs are very important to the degradation rate of dye molecules. DTWS-4-Ag composite material makes wood pore diameter and Ag NPs production reach a high balance, so that it has the highest degree of reduction. DTWS-4-Ag showed high catalytic degradation efficiency and stability for methylene blue degradation, with the degradation efficiency up to 98.3 %. This low-cost, renewable wood-based filter has high dye degradation efficiency and can be widely used in practical wastewater treatment. [Display omitted] • DTWS-Ag membranes modified by low eutectic solvent method were prepared. • Partial removal of lignin and hemicellulose improves degradation efficiency. • Catalytic activity of material was inhibited by excessive removal of components. • The membrane showed good removal of highly concentrated dye solutions. [ABSTRACT FROM AUTHOR]

Recently, using wood composite materials as microwave absorbers has attracted much attention. This comprehensive review considers using wood raw materials such as carbon, metal/oxide metal, and polymer composites as fillers to develop microwave absorbers. The review covers various aspects, such as the electromagnetic properties of wood composites, the influence of fillers on microwave absorption properties, manufacturing methods, microstructure characterization, microwave absorption performance, and potential for industrial applications. In addition, the ecological sustainability aspects of using wood composites as microwave absorbers are also discussed. This review aims to provide valuable insights for researchers and professionals involved in developing and applying wood composites as microwave absorbers by providing a comprehensive overview. • Wood composites for microwave absorber applications. • Wood composite materials have good mechanical properties. • Wood composites are an environmentally friendly alternative material. • Teak and poplar wood composite show the lowest RL is ∼64 dB. • This review is helpful for researchers and industries of wood-based microwave absorbers. [ABSTRACT FROM AUTHOR]

Using engineered wood products (EWPs) in the building technologies is very crucial in terms of sustainable approaches. They provide; low weight, high structural stiffness, carbon storage capacity and easy erection on site. EWPs are composite materials that are influenced by a variety of factors that play a critical role in their formation. The chemical ingredients of the wood, the curing process of the adhesive, the type of wood, the relationship between the adhesive and the wood species, the curing temperature, the geometric configuration of the lamellae, etc. can all be included under the heading of these factors. In contrary with massive wood, to obtain EWPs different types of adhesives can be used. Therefore adhesive type and its application method affects the quality of wooden structural element. Choosing the appropriate adhesive is one of the steps to be taken to obtain the structurally correct product. Based on this approach, it was decided to investigate the adhesion performance of different adhesive types. This paper aims to present the best bonding method among the melamine urea formaldehyde (MUF) and epoxy adhesives by considering the fiber directions of the wood and the type of adhesive according to the load. One of the aims of this study is to investigate the effect of changing the fiber direction of wood on adhesion performance, taking into account the current gap in the literature. Pull-off tests were conducted to assess the bonding performance of different types of adhesive in wood samples with varying fiber direction. The wood samples were bonded to the wood surface with varying grain directions. During the pull-off tests, ruptures in the glue line of the test samples were commonly observed. The results have shown that in cylindrical samples bonded with epoxy, the highest bonding strength values were observed in scenarios where the wood fibers were oriented parallel to the load direction and perpendicular to the ground plane. Similarly, for wood samples used as the bonding surface, the highest bonding strength values were achieved when the wood fibers were oriented parallel to the load direction and perpendicular to the surface plane. On the other hand, the highest value in pull-off test setups was found with melamine urea formaldehyde adhesive; commonly used in laminated timber, between the wood samples with grains perpendicular to the load direction and the wood adherence surfaces with a parallel grain direction. In summary, the highest strength value was obtained from the test setup in which epoxy was used as the adhesive and both the wood specimens and the wood bonding surface had fiber directions parallel to the load direction. • The fiber directions of wood in terms of bonding performance are evaluated. • Epoxy provides stronger adhesion than MUF in EWP's technology. • The parallel grain direction of wood exhibits the strongest bonding performance relative to the applied load. • The perpendicular direction of the wood fibres to the applied load is the most critical point in terms of strength. [ABSTRACT FROM AUTHOR]

In order to overcome the consumption of non renewable resources and serious environmental pollution caused by traditional petroleum based polymers, blending and modifying renewable PLA and wood fibers to replace traditional petroleum based plastics has become a current research hotspot. However, due to the large polarity difference between PLA and wood fibers, the performance of the composite material prepared is not ideal. To improve the performance of polylactic acid/poplar fiber (PLA/PF) composites and simplify the process, this study used cellulase and 2,2 '- (1,3-phenylene) - dioxazoline (PBO) co modification, a safe, environmentally friendly and simple process, to prepare the composites. The results show that the crystallization properties of cellulase and PBO-modified composites will be appropriately reduced, the microstructure shows that the interface of PLA/CF -5.5 /PBO is more tightly bonded, and the mechanical test results show that the modified material has excellent mechanical properties. Compared to the unmodified PLA/PF, PLA/CF -5.5 /PBO has a 28.85% increase in tensile strength, reaching 63.65 MPa. while its flexural strength reaches 116.07 MPa, representing a 21.45% increase. Surprisingly, the tensile and strength of PLA/CF -5.5 /PBO exceeds that of pure PLA, with the flexural modulus showing a significant increase of 43.96% compared to PLA. The above analysis shows that the effect of the two synergistic modification methods is significant, and the research results provide an environmental protection idea for the development of PLA matrix composites with high compatibility, good mechanical properties and good environmental adaptability, and broaden the application scope and value of the composites. [Display omitted] • Cellulase-treated wood fibers are eco-friendly, energy-saving, simple process. • New method: synergistic enhancement of PLA with wood fiber treated by cellulase and PBO. • The mechanical properties of PLA/CF -5.5 /PBO are at a high level in the research field. • PLA/CF -5.5 /PBO has higher tensile, flexural strength and modulus than pure PLA, adding 20% wood fibers reduces cost. [ABSTRACT FROM AUTHOR]

Transparent wood includes a group of composite materials consisting of a renewable component (various wood species) and a refractive-matching index polymer (petroleum or bio-based) with a wide range of applications. There are various types of polymers used for transparent wood preparation Due to their favourable optical, mechanical, and carbon-storing properties, transparent wood is ideal for use in, e.g., the automobile industry, construction, packaging, or electronics. In this study, acrylic-based transparent wood was prepared by deactivating chromophore groups in natural basswood (Tilia cordata , L.), followed by a subsequent vacuum-assisted 2-hydroxyethyl-methacrylate polymer infiltration. Fire characteristics, UV and biological resistance of this wood-polymer system were investigated. Transparent wood prepared for this study shows high resistance to wood decay fungi. Fire performance test shows higher resistance to initiation (higher time to ignition and critical heat flux)compared to natural wood and lower yields of carbon monoxide. When exposed to UV irradiation, colour, and transmittance change intensively only in the first hours of exposure, then only very gradually. On the other hand, transparent wood shows higher values of heat release rate and derived parameters. • Acrylic-based TW has strong resistance to fungi that cause wood degradation. • Acrylic-based TW has greater fire initiation resistance compared to raw wood. • Compared to raw wood, acrylic-based TW emits less carbon monoxide. • Its optical characteristics change dramatically when exposed to UV radiation. • In comparison to raw wood, Acrylic-based TW exhibits greater values of HRR rate. [ABSTRACT FROM AUTHOR]

Abstract New composite materials based on sawdust as reinforcing material and polyurethane foam as a binder agent, exhibiting sound absorbing proprieties, have been obtained. Due to the sound-absorbent proprieties exhibited by these type of materials, 11 new composite systems have been obtained varying the type and the size of sawdust particles, the percentage of binder and the thickness of material. The sound absorption properties of the new obtained materials are directly correlated with the composition, the thickness of materials as well as the air gap samples and the rigid wall. In addition, the morphological and thermal conductivity proprieties and the mechanical ones, of the new obtained materials, were carried out. Highlights • New composite materials with improved sound absorbing proprieties were obtained. • Sound absorbent proprieties are correlated with the sawdust nature and dimension. • The air spaces trapped in the structure lead to additional acoustic absorption. [ABSTRACT FROM AUTHOR]

Abstract Presented work discusses comparative studies of the use of a hybrid filler system on the properties of polypropylene and poly(lactic acid) composites. Wood flour have been added to improve the initially poor material performance of cork based composites. The hybrid cork/wood filler system used during this study was introduced to polymer system by two step extrusion/injection molding process in the amount of 10, 20 and 30 wt%. Samples were subjected to detailed thermo-mechanical and structural analysis. The investigated hybridization method was successfully implemented, leading to the enhancement of mechanical characteristics comparing to pure cork composites. Density analysis in combination with structural observations, confirmed significant changes in the morphology of cork, including the loss of the cellular structure, due to high shearing of the injection molding process. The favorable results of water absorbency tests indicate the potential use of cork filler to improve the dimensional stability of composites. [ABSTRACT FROM AUTHOR]

Abstract Optically transparent wood (TW) is an emerging candidate for applications in energy efficient buildings. In this study, anti-ultraviolet and infrared heat shielding TW was prepared based on the delignification of the wood's substrate. This was followed by infiltration of pre-polymerized methyl methacrylate (PMMA) with modified antimony-doped tin oxide (ATO) nanoparticles. The ATO addition enhanced the interfacial bonding among the compounds, which improved the fracture strength, leading to a high fracture strength of 96.4 MPa and modulus of 4.27 GPa with addition of 0.3% ATO. Furthermore, the obtained ATO/TW exhibited high transparency, excellent near infrared (NIR) heat shielding performance, and ultraviolet (UV) shielding properties according to the ultraviolet–visible spectrophotometer measurement, the infrared heat shielding simulation test, and the UV-shielding test. The TW treated with 0.3% ATO still maintained a very low thermal conductivity of around 0.2 W m−1 K−1. After addition of 0.7% ATO, the obtained TW had a quite low UV transmittance of ＜20%. The Aspergillus niger maintained high viability after UV irradiation treatment when shielded with TW treated with 0.7% ATO. The findings indicate that the multifunctional and durable ATO/TW has a potential to be used as energy-saving building material. [ABSTRACT FROM AUTHOR]

Abstract This paper presents the results of an experimental study that explores the ignition and combustion of composite fuels based on wood processing and oil production wastes. By the example of a typical developed industrial region, it is shown how numerous of wood processing wastes (sawdust) and oil production wastes (sludge) may be effectively recovered. We study the main time characteristics (ignition delay and combustion duration) of fuel combustion, heat release, anthropogenic emissions. The values of relative efficiency (taking into account energy, environmental and economic indicators) of waste-derived composite fuels are defined in comparison with fuel oil and coal. The optimal concentration of components – 50% of sawdust, 25% of oil component, and 25% of water – allows the maximum efficiency of fuel combustion. In terms of minimizing the cost of ignition, the best is the mixture of 30% of sawdust and 70% of heavy oil. The research findings illustrate the great prospects for the large-scale involvement of numerous wastes in the fuel and energy cycle of any industrially developed region of the world. Graphical abstract Image 1010 Highlights • Sawdust can be used as main and additional components of waste derived fuel. • Composite fuels are attractive compared with coal and fuel oil. • Relative efficiency of composite fuels based on sawdust and oil may amount to 0.3–12.9 • Relative efficiency is maximum for the fuel: 50% sawdust, 25% oil component, 25% water. • Even a small addition of water significantly decrease emissions from fuel combustion. [ABSTRACT FROM AUTHOR]

Abstract Recycling of construction and demolition waste (CDW) which contains materials with high resource value such as plastics, metals, wood, glass and concrete has been investigated in recent years due to tightening environmental legislation. Wood-plastic composites as an environmentally friendly material provide a possibility to enhance the recycling of material. The effect of the addition of CDW on the mechanical and moisture properties of WPC is studied in this paper. Three types of wood-plastic composites were manufactured with different amounts and composition of a CDW filler. Their properties were compared to the reference composite manufactured with virgin wood fibers and polypropylene as the polymer. It was found that the addition of the CDW filler weakened the mechanical properties of the composite generally, except for the fact that the Charpy impact strength was improved significantly. Minor variations in the composition of the CDW filler did not have an impact on the mechanical properties, but an increase in the amount of filler increased the deterioration of mechanical properties. For moisture properties, the addition of the CDW filler decreased the water absorption and thickness swelling of the composites. An increase in the filler content improved the thickness swelling more significantly than water absorption. [ABSTRACT FROM AUTHOR]

Abstract Wood is a natural engineering material that has traditionally been exploited in design for a wide variety of applications. The recent demand for sustainable material and construction processes in the construction industry has triggered a renewed interest and research in the inherent properties of wood and their derived applications, and specifically for developing low-tech architectural adaptive systems. This paper focuses on the physical and computational modeling of the morphing behavior of wood through hygroscopic expansion or contraction to a high degree of precision. The amount of stress related to the hygroscopic shrinking or swelling ranges from almost zero to high values, and its prediction is fundamental to alleviate any fatigue challenges. The capability of designing wood composite whose stress state remains limited under changes of the environmental humidity is beneficial for any engineering application subjected to a repeated reversal of loading such as adaptive systems. In this paper, a mechanical model, together with its numerical implementation, is presented; the model is benchmarked against some prototypical experiments, performed by using real material parameters. The control parameter in the model is the relative moisture change in wood that determines the orthotropic swelling/de-swelling phenomenon, and is coupled with the elastic behavior of wood. This model is integrated into a programmable matter design approach that combines physical and computational exploration. The approach is illustrated for a hygro-morphic building façade panel. The approaches and algorithms presented in this paper have further applications for computer-aided design of smart materials and systems with interchanging functionalities. Highlights • Physical exploration of the effect of wood characteristics on its morphing behavior. • Generalized orthotropic model for both elastic and hygroscopic behavior of wood. • Physical and numerical programmable matter approach for hygroscopic adaptive systems. [ABSTRACT FROM AUTHOR]

Abstract The use of Glass Fiber Reinforced Polymers (GFRP) can delay or prevent tension failure in timber beams under loading and highly reduce tensile stresses. In this paper, the problem of reversibility, compatibility, and poor performance at high temperatures, of "traditional" organic adhesives was mitigated through the use of metal connectors. The flexural behaviour of hardwood and softwood beams reinforced by mechanically connected GFRP plates, has been studied through series of experimental investigations and numerical modelling. The experimental program included strengthening and testing of a total of 91 beams (50 hardwood and 41 softwood). Each beam was loaded above its service load until complete failure. Different strengthening layouts and quantity of metal connectors were used. The increment in capacity and stiffness is the main focus of this paper and effects of strengthening on deflection, failure load and failure mode, strain, and beam ductility were discussed in details. The combination of different GFRP configurations with appropriate amount of metal connectors, led to the doubling of the maximum load carrying capacity of the beams. [ABSTRACT FROM AUTHOR]

Timber-mortar composite structures require rigid, strong, but also ductile connections to optimize their performances. Up to now, the preferred connection systems were based on metal fasteners and notches in wood. In this study, an alternative approach based on a fully glued connection was studied (using an epoxy-based system), and a wood pre-treatment was applied in order to enhance the compatibility and the adhesion properties at the interface between beech wood and mortar. The wood surface was functionalized with a xerogel obtained by means of a sol-gel process, consisting of two layers of silane nanofilms – namely tetra-ethoxysilane and (3-Aminopropyl) triethoxysilane. Chemical analysis of the wood surface confirmed the chemical bonding of the silanes. Microscopy images revealed that the silane pre-treatment also affects adhesive penetration into the wood. In terms of mechanical properties, 3-point bending tests on pre-treated beech wood-mortar samples showed an improved load bearing capacity in comparison to unmodified wood-mortar specimens. [ABSTRACT FROM AUTHOR]

• The modification of the geometry of a flat thin panel into a corrugated shape is an effective mechanical strengthening mechanism. • The mechanical properties of corrugated panels in the longitudinal direction are superior to those in the transverse direction. • Corrugated panels do not individually have sufficient mechanical performance to be an alternative to plywood and OSB. • I-Joist with a corrugated web seems to be the best potential structural application for corrugated panels. Typically, wood-based structural materials and their constituents are rectangular and full shapes. It is rare to find a periodic geometry such as the corrugated shape in these wood-based materials, whereas this geometry is very common in advanced composite materials. This project aims to characterize wood based corrugated panels in order to use them as a structural composite. The corrugated panels were characterized in terms of compressive, tensile, and bending properties in the direction parallel and perpendicular to the panel corrugations. Among the structural applications that could be developed, I-joists with corrugated panel-based web seem to be the most promising option. [ABSTRACT FROM AUTHOR]

Activated carbon (AC) prepared from Jatropha curcas and graphene oxide (GO) were employed in the preparation of natural polymer based wood starch composites (WSC) through the solution blending technique using water as a solvent. In this study, methyl methacrylate (MMA) was grafted onto the starch polymer and this MMA grafted starch (MMA- g -starch) was cross-linked with the cheap soft wood flour using the citric acid as cross-linker and water as a solvent in the whole process. The prepared GO and AC were characterized through Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD), thermogravimetric analysis (TGA) and Raman study. The interaction of GO and AC, with MMA- g -starch, citric acid and wood were studied by FTIR, XRD and SEM analysis. The GO and AC treated composites exhibited outstanding mechanical properties, thermal stability and fire resistance properties. The tensile strength of the composites increased by 178% and 200% with addition of 2 phr AC and GO respectively compared to untreated composites. A significant enhancement in water resistance properties of GO and AC treated composites was also attained. The study showed that the properties of the composites containing AC prepared from the seeds of Jatropha curcas was quite comparable with the composites reinforced with GO. [ABSTRACT FROM AUTHOR]

“Wood Plastic Composite” or WPC is becoming increasingly popular in outdoor applications because of the advantage of a better durability in wet environments compared to natural wood. The possibility of using WPC as a sound barrier, or as façade cladding, is investigated in this paper. The sound transmission loss (TL) of an orthotropic WPC panel, obtained by coupling together several boards, is computed by means of the transfer matrix method. The plate is modelled as a thin orthotropic layer, described by frequency dependent elastic properties. A numerical procedure, based on a finite element simulation, is proposed in order to determine the stiffness properties along the principle direction of the panel. The reliability of this approach is verified by comparing the numerical results with the experimental stiffness measured on a WPC beam. The orthotropic behaviour is approximated by an elliptic interpolation of the flexural stiffness along the two principle directions, based on a simplified assumption which considers the in-plane shear modulus proportional to the orthotropic elastic moduli. The model based within the transfer matrix method framework is validated with the experimental transmission loss measured on a WPC panel in a reverberant room. Finally, the possibility of increasing the acoustic performance of WPC structures by optimising their cross-section is investigated. [ABSTRACT FROM AUTHOR]

Composite finger-jointed spruce and oak wood panels have been thermally treated under standard pressure and oxygen content conditions at two different temperatures, 180 °C and respectively 200 °C for short time periods (3 and 5 h). Due to the thermally-aided chemical restructuration of the wood components, a decrease in water uptake and volumetric swelling values with up to 45% for spruce and 35% for oak have been registered, comparing to the reference samples. In relation to water resistance, a 15% increase of the dispersive component of the surface energy has been registered for the thermal-treated spruce panels, which impedes water spreading on the surface. The thermal-treated wood presents superior resistance to accelerated UV exposure and subsequently, with up to 10% higher Brinell hardness values than reference wood. The proposed thermal treatment improves the durability of the finger-jointed wood through a more economically and environmental friendly method than traditional impregnation, with minimal degradative impact on the structural components of wood. [ABSTRACT FROM AUTHOR]

Phase change materials applied in the thermal insulation of building or storage system are beneficial to slow down internal temperature fluctuation and decrease energy consumption. Visible temperature change can provide convenience for people's production and life. In this work, the thermochromic delignified wood composite phase change materials (TCDWs) composed of thermochromic (TC) compound and delignified wood (DW) are fabricated by vacuum-assisted impregnation method. Various techniques are applied to characterize mechanical and thermal properties of TCDWs. Results indicate that TCDWs exhibit suitable phase change temperature, large latent heat, good thermal reliability, as well as excellent thermal stability and mechanical properties. More importantly, TCDWs have excellent reversible thermochromic ability and visibly show the phase change progress and temperature by color change from dark blue to off-white. The thermal insulation ability of TCDWs can reduce heat flow and heat exchange between inside and outside environment, maintaining the internal temperature for longer time. The largest absorption capacity of DW is 65%, which is 15% more than that of pristine wood (PW). The excellent reversible thermochromic, thermal and mechanical properties of TCDWs have great potential in thermal energy storage applications including thermal insulation, decoration, furniture, storage and building energy conservation. [ABSTRACT FROM AUTHOR]

Nanocellulose is a high value material that has gained increasing attention because of its high strength, stiffness, unique photonic and piezoelectric properties, high stability and uniform structure. Through utilization of a biorefinery concept, nanocellulose can be produced in large volumes from wood at relatively low cost via ionizing radiation processing. Ionizing radiation causes significant break down of the polysaccharide and leads to the production of potentially useful gaseous products such as H 2 and CO. The application of radiation processing to the production of nanocellulose from woody and non-wood sources, such as field grasses, bio-refining by-products, industrial pulp waste, and agricultural surplus materials remains an open field, ripe for innovation and application. Elucidating the mechanisms of the radiolytic decomposition of cellulose and the mass generation of nanocellulose by radiation processing is key to tapping into this source of nanocelluose for the growth of nanocellulostic-product development. More importantly, understanding the structural break-up of the cell walls as a function of radiation exposure is a key goal and only through careful, detailed characterization and dimensional metrology can this be achieved at the level of detail that is needed to further the growth of large scale radiation processing of plant materials. This work is resulting from strong collaborations between NIST and its academic partners who are pursuing the unique demonstration of applied ionizing radiation processing to plant materials as well as the development of manufacturing metrology for novel nanomaterials. [ABSTRACT FROM AUTHOR]

A Dielectric Barrier Discharge (DBD) torch has been designed for the treatment of several wood species and composites. This paper presents some results obtained onto Medium Density Fiberboard (MDF) samples. The aim of the treatments was to improve their wetting properties. Tests made before and after treatments showed improvements of surface wetting and have been correlated with surface chemical composition. It also has been shown that the treatment effect is ephemeral. [ABSTRACT FROM AUTHOR]

In order to study the factors that influence the bonding capacity of the bonded interface formed between carbon fiber reinforced polymers (CFRP) and wood, 10 groups (30 total samples) of CFRP-wood specimens were designed. The development law of CFRP plate strain was analyzed, and the effects of the bonded width and length of CFRP sheet to the wood as well as the damage rate of wood on the bonding capacity of the interface were discussed. The test results showed that the stress was gradually transmitted from the loaded end to the free end of the sample. The loading was a process of continuous energy accumulation. When the specimen entered its limit state, the interface was in the maximum stress state, and the accumulated energy was also the largest, resulting in sample failure by brittle fracture. The bonded width of CFRP sheet had a significant effect on the interfacial bearing capacity. The presence of the initial damage in the wood samples destroyed the integrity of the fiber on the wood surface, thus reducing the bearing capacity of the interfacial bond in the composite materials. The bond bearing capacity decreased with an increase in the preexisting damage rate of the wood. In this paper, a calculated expression for the interface stress distribution under the limit state was derived by analyzing the force in micro sections of the bonded interface. The bond bearing capacity model for CFRP-wood interfaces was established and verified with the experimental results. The prediction curve of the interface bond bearing capacity model was in good agreement with the experimental results. [ABSTRACT FROM AUTHOR]

The size and shape of powdered wood particles are important properties when considering their use in wood burning or the production of biofuels, biocomposites and biochemicals. Different measurement techniques can be used to measure particle size, but unfortunately these do not provide information about the shape of the wood particles. In this study, a fast and reliable tube flow fractionation method (analysing time 3min; particle size range 1 μm-2000 μm; analysed particles per sample 30,000–200,000) is used to separate water-diluted wood powders which varies by size and shape. 30 different milled wood powder samples are analysed (average particle size from 20 μm to 300 μm and average aspect ratio from 3 to 10). The major benefit in tube flow fractionation method is that the concealment of the finest particles in CCD imaging is avoided by applying the imaging unit after the fractionation of wood particles. Wood powder can easily be separated into different fractions by leading the water-diluted sample flow into different beakers for certain time periods. The transmittance signal after tube flow fractionating yields information about the particle size, and optical imaging provides information about the morphology of the particles. It was found in this study that rotor impact milling to a finer size range produces small but elongated particles. Additionally there were only small differences in the particle size distributions between jet milled and oscillatory ball milled samples, but it was noticed that oscillatory ball milled powders have a significantly lower aspect ratio than jet milled samples. [ABSTRACT FROM AUTHOR]

Carbon fiber-reinforced polymer (CFRP) bonding technique can provide an adequate enhancement to wood structures. Varying temperature levels can affect the strengthening by CFRP, particularly the interfacial behavior of CFRP-wood composite, while the fundamental mechanism is still not clear. This research aims to evaluate the temperature effect on interfacial bonding of CFRP-wood composite, and to explore the fundamental mechanism by using molecular dynamics (MD) simulations. After the specimens are conditioned at various temperature levels, the interfacial bonding performance of CFRP-wood composites is evaluated by acoustic-laser technique and shear test. The results indicate that the bonding is strong at low temperature and deteriorates at high temperature. Meanwhile, the fracture energy measured from the shear test and the MD simulation shows a similar trend, which decreases as the temperature level increases. It is found that the constituent materials deteriorate with increasing temperature, as evidenced by the conformational changes of the modeled epoxy-wood interface, which significantly weakens the interfacial bonding. The finding unveiled from our study demonstrates that the long-term exposure to high temperature can significantly deteriorate the CFRP-wood composite and consequently lead to a structural failure ahead of its service life, which should be considered particularly in tropical and subtropical regions. [ABSTRACT FROM AUTHOR]

At present, since wood resources are in short supply, it is of great significance to utilize wood residues to prepare bio-composites for sustainable developments. Compared with the preparation of traditional transparent materials using solid wood, making transparent materials using wood fibers (WF) can utilize wood residues (such as wood chips, wood strips, sawdust, etc.) as the raw material sources, which can help the environmental protection and promote energy saving features of transparent fiber wood (TFW). Currently, the method of making TFW usually uses simple chopped wood residues with the removal of lignin. The transparent composites using WF were prepared by impregnating pre-polymerized polymers. Therefore, this study adopted a method of wood powders (WPF) screening to solve this problem. The wood residues were smashed into a certain mesh size of WPF, and then the epoxy resin (EP) was impregnated into the delignified WPF to successfully prepare the wood powder-reinforced transparent wood (TCWP), which effectively optimized the preparation process and improved the efficiency. The preparation efficiency is greatly improved by more than 50%. The effects of length-diameter ratio and mass fraction of WPF on optical properties, mechanical properties and thermal conductivity of TCWP were further investigated in this study. The comprehensive analysis showed that, when the WPF size was 80 mesh and the fiber mass fraction was 5%, it had the best optical, thermal, and mechanical properties. In addition, the laser scattering experiments showed TCWP can be used as an optical screen and architectural glass in the engineering practice and became a transparent composite material with high added value, because of the uniformity of WPF dispersion in EP, resulting in more uniform light passing rate and increased haze. [Display omitted] • Wood fiber transparent materials with powdered wood are prepared. • The preparation efficiency is greatly improved by more than 50 %. • The optical, thermal, and mechanical properties are further optimized. • The effects of length-diameter ratio and mass fraction of wood fiber are analyzed. • The uniformity of wood powder fiber leads to higher haze and scattering angle. [ABSTRACT FROM AUTHOR]

• Wood was reengineered into a high-strength and light-weight bio-composite material. • Wood was delignified through an efficient ultrasound-assisted organosolv process. • The composite's epoxy resin matrix was synthesized from the extracted lignin. • Wood-based composite showed specific mechanical properties in the range of metals. • Compositing improved wood's hydrophobicity, antioxidation and thermal stability. The preparation of wood composites involves long preparation steps and non-renewable matrices while generating lignin waste without high-value utilization. Here, we present a reengineering approach to developing a high-strength and lightweight bio-composite material through fractionating natural wood into highly porous delignified wood (DW) and lignin, synthesis of a lignin-based epoxy resin (LER), followed by composting the DW and the LER. The newly developed wood-based composite has drastically improved properties of hydrophobicity, antioxidation and thermal stability, and more notably extraordinary mechanical properties superior to many metal alloys. Hence the reengineered wood composite developed can be a renewable functional material for structural applications. [ABSTRACT FROM AUTHOR]

• Fabrication of wood-derived free-standing hierarchical porous carbon frameworks. • Effective control over the density and pore structure of the carbon skeleton. • The assembled Li-S battery exhibits good rate performance and cycling stability. Lithium-sulfur batteries have the advantages of high specific capacity and low cost, but are subject to poor rate and cycle performance. In this work, we prepared wood-derived hierarchical porous free-standing carbon framework materials as three-dimensional conductive current collectors to assemble high-performance lithium-sulfur batteries. The micron-scale pores of wood are conducive to the diffusion of electrolyte, and the introduction of a large number of nanopores on the carbon skeleton can inhibit the dissolution and shuttle effect of lithium polysulfide, and improve the rate and cycle performance of the batteries. The porous carbon framework is density-adjustable and free-standing, and the battery has a specific capacity of 1120 mAh/g with good rate performance. The capacity decay are only 0.11%/cycle and 0.08%/cycle respectively under 0.5 C and 1 C after 500 cycles. In addition, wood is inexpensive and renewable, and the batteries are assembled without conventional conductive agents, binders and current collectors. [ABSTRACT FROM AUTHOR]

Biomorphic SiC is a SiC/Si composite made by the reactive infiltration of molten silicon by capillarity into a carbon preform from high-temperature pyrolysis of a wood porous precursor. When excess silicon is removed, a hierarchically porous SiC material with highly interconnected porosity is obtained. By choosing different wood precursors, different pore size distributions can be obtained thus tailoring the resulting properties. We study the thermal conductivity of porous biomorphic SiC from five different precursors, including a recycled wood product, in order to determine the microstructure-conductivity correlation. Here, we remove the excess of silicon by a high temperature capillary extraction-evaporation method. We used the laser flash technique to measure thermal diffusivity in the range ~300 K to 973 K, in order to determine the thermal conductivity. Thermal conductivities in the range 4–88 W/m K were achieved. The temperature, porosity, pore shape and orientation, and the treatment used to remove the remaining silicon all have a significant impact in the resulting thermal conductivity. We explain this influence in a first approximation in terms of a geometrical model. [ABSTRACT FROM AUTHOR]

In this study, the effect of using nano-sized zinc oxide (ZnO) particles on the enhancement if the degradation resistance of wood-high density polyethylene (HDPE) composite was investigated through artificial weathering. Samples with different amounts of ZnO mixing ratio (0, 1, 2, and 4 wt%) were manufactured using an internal mixer followed by compression molding. The prepared samples were then exposed to the artificial weathering process in a QUV weatherometer. The weathering behavior of samples was characterized using tensile strength, contact angle analysis, colorimetry, ATR-FTIR spectroscopy and FE-SEM. The results indicated that the amount of surfaces crack, tensile strength loss and contact angle changes decreased as a function of ZnO addition, while lightness changes were not affected. Analysis of the functional groups at the composite surface by ATR-FTIR showed that the incorporation of nano-sized ZnO particles in the composite formulation changed the degradation mechanism of composite to photocatalytic reactions, leading to the production of high levels of zinc carboxylate in the structure of weathered composite. [ABSTRACT FROM AUTHOR]

In this paper we investigate micro–macro mechanical relations in Palmetto wood, a natural composite, by means of a computational homogenisation-based multi-scale modeling approach. The homogenisation procedure is solved sequentially at multiple length scales by following a bottom-up approach. The proposed strategy consists of homogenising the three length-scales by means of representative volume elements of material. The resulting effective macroscopic properties allow us to compute the mechanical response of individual macro-fibres and bulk wood specimens by means of a standard finite element procedure. The numerical predictions are compared successfully with experimental measurements. Following the validation, a parametric study is performed to investigate the micro–macro relations in Palmetto wood. The influence of several micro-structural features present at different length scales are investigated, such as the cellulose content and its crystallinity, the microfibril angle, the cell-wall thickness of micro-fibres, and the porosity of macro-fibres and their surrounding matrix, among others. The effects of such microscopic parameters are investigated on the Young’s modulus and density of Palmetto bulk wood. These results show that the present strategy can pave the way for further studies on complex microstructure–property relationships existing in different wood species, and on the possible development of more advanced bio-inspired composite materials. [ABSTRACT FROM AUTHOR]

Photocurable composites based on a UV-light curable methacrylic-siloxane resin formulation and various concentrations (5 ÷ 20 wt%) of microcrystalline cellulose powder (MCC) were prepared and characterized to assess their suitability as protective coatings for wooden artworks. Dynamic mechanical thermal analysis highlighted that MCC promoted an enhancement of both storage and loss moduli and a decrease of the thermal expansion coefficient. Interestingly, the flexure elastic modulus and the flexure maximum stress of the neat photoresin increased upon the filler addition without any embrittling effect. An increment of hydrophobicity (contact angle), surface hardness (Shore D and pencil scratch tests) of the neat UV-light cured matrix even at the lowest filler loading was observed. These promising results suggest that the photo-curable microcomposites could be able to recover the mechanical and physical properties of damaged wood and replace the traditional resins soluble in toxic solvents utilized in this kind of restoration works. [ABSTRACT FROM AUTHOR]

In this study, the Poly(vinyl alcohol)(PVA)/wood powder composite was prepared through combining the novel technologies of solid-state shear milling (S 3 M) and thermal processing of PVA, which provided a large-scale and non-solvent way to efficiently utilize the abundant biomass materials. The results showed that S 3 M can significantly promote pulverization, dispersion, mechanical activation, and interfacial compatibility of the components, endowing the materials with better processability and mechanical performances. The XRD and FTIR results showed that with the increasing of milling cycles, the hydrogen bonds of PVA molecules were partially destroyed, leading to the formation of looser crystalline structure and lower crystalline degree, while the hydrogen bonding between PVA and wood powder was strengthened. Combining with thermal processing technology of PVA, the composite treated by S 3 M had a good processability and mechanical properties. DSC curves revealed that the melting temperature of PVA/wood powder (70 wt/30 wt) composite decreased to 123 °C, providing a quite wide thermal processing window for composite. High-pressure Capillary rheology analysis showed that the shear viscosity of the composite decreased with the increasing milling cycles. Finally, the composites exhibited significant improvements in mechanical properties. The tensile strength increased from 16.6 MPa to 22.5 MPa, and the elongation at break increased from 32.0% to 120.5%, respectively. [ABSTRACT FROM AUTHOR]

This work presents the effect of temperature on mechanical properties and tensile creep responses of Wood/PVC (WPVC) composite materials. The materials were produced by an industrial scale twin crew extruder using the weight ratio of wood and PVC compound of 1:1. The tensile, compressive, and flexural properties were determined at various temperatures (25 °C, 40 °C, 50 °C, 60 °C, and 70 °C). The tensile creep responses and creep models at these temperatures were also included in this work. The experimental results indicate that mechanical strength of WPVC composites decreased significantly at temperature higher than 50 °C while the modulus of elasticity was affected significantly at temperature higher than 60 °C. The material properties at large deformation as mechanical strength was found to be more sensitive to the temperature change than the mechanical modulus at small deformation. The empirical equation representing mechanical properties as a function of temperature was also provided together with recommended adjustment factors for the design phase. The creep models combining time–stress dependencies using power form and time–stress–temperature dependencies using Pickel’s form were obtained. Close agreement was observed representing adequacy of these models to predict the long-term deformation of the WPVC composites. This provided information would be useful for the design of WPVC composite member in structural and construction applications. [ABSTRACT FROM AUTHOR]

Wood–plastic composites were injection-molded from recycled acrylonitrile–butadiene–styrene and polystyrene from post-consumer electronics in the interest of resource efficiency and ecological product design. The wood content was raised in two steps from 0% to 30% and 60%. Reinforcement performance of recycled particleboard was compared to virgin Norway spruce. Styrene maleic anhydride copolymer was used as the coupling agent in the composites with a 60% wood proportion to investigate the influence on interfacial adhesion. The composites were characterized by using physical and mechanical standard testing methods. Results showed increased stiffness (flexural and tensile modulus of elasticity), water uptake and density with the incorporation of wood particles to the plastic matrices. Interestingly, strength (flexural and tensile) increased as well. Wood particles from Norway spruce exhibited reinforcement in terms of strength and stiffness. The same results were achieved with particleboard particles in terms of stiffness, but the strength of the composites was negatively affected. The coupling agent affected the strength properties beneficially, which was not observed for the stiffness of the composites. The presence of cadmium, chromium, copper, arsenic and lead in the recycled resources was found by an elementary analysis. This can be linked to color pigments in recycled plastics and insufficient separation processes of recycled wood particles for particleboard production. [ABSTRACT FROM AUTHOR]

Flame retardancy of wood-plastic composites (WPC) needs to be improved to widen the applications for these composites. This may be accomplished by protecting both polymer matrix and wood filler with a fire-retardant (FR). In this study, hardly inflammable particleboard converted into wood flour (B1-particleboard flour) was used in combination with several halogen-free FRs. The fire performance and thermal properties of the WPC (matrix: recycled polypropylene) were investigated using limiting oxygen index analysis (LOI), a modified single-flame source test, fire shaft test and thermogravimetric analysis (TGA). The combination of B1-particleboard flour, expandable graphite and red phosphorous led to the highest LOI (38.3). However, at the same time, relatively high water absorption of this formulation was observed which was attributed to the reaction of ammonium polyphosphate in the B1-particleboard flour and red phosphorous which was added during the compounding step, leading to increased hydrophilicity of the composite. The combination of B1-particleboard flour and ammonium polyphosphate (APP) or phosphorized expandable graphite to protect the polymer matrix offered the best overall performance when taking into account LOI (here: 34–35), tensile strength, modulus of elasticity and water absorption values. The WPC-formulation including B1-particleboard flour and APP did not pass the requirements of the German fire shaft test according to DIN 4102-1, however, the duration until smoke gas temperature exceeded 200 °C was more than doubled compared to a commercial WPC-profile based on PP without fire-retardants. The modified single-flame source test showed that all WPC formulations were self-extinguishing. [ABSTRACT FROM AUTHOR]

Wood-plastic composites (WPCs) with excellent water resistance, light absorption, mechanical properties, and thermal stability features were fabricated on an assembled nano-interface using cationic polyethyleneimine-nano-ZnO (PEI-ZnO) and anionic sodium polyacrylate-wood (PAAS-wood). The charge grafting, assembly, and dispersive morphology on the wood surface were analyzed by ZETA potentials, SEM images, crystal features, XPS and FTIR spectra. With a three dimensional shielding-assembling nano-network, water absorption of wood-polypropylene composite decreased from 5.20 wt.% to 1.83 wt.%, and the decomposition temperature (Td) of wood and polypropylene were enhanced by 114 °C and 63 °C depending on passing and hindering. The tensile strength and the glass transition temperature (Tg) were enhanced from 20.42 MPa, 11.7 °C to 38.73 MPa, 33.21 °C, respectively, likely due to firmed nano-dispersion, strong interfacial adhesion, and sufficient load transfer. In addition, ultraviolet and near-infrared resistance of the composite were found to be promoted by adopting the assembled nano-interface. [ABSTRACT FROM AUTHOR]

Wood is a versatile composite material consisting of natural macromolecules, including carbohydrates (cellulose, hemicelluloses) and lignin. As a natural biological material, wood undergoes photooxidation phenomena under environmental factors action. Colour modification of wood surface is a primary consequence of the photooxidation phenomena. One way to prevent wood photodegradation consists in coating it with protective layers by chemical modification of the surface. The aim of this study is related to the photostability evaluation of chemically modified softwood by successive treatment stages with succinic anhydride and epoxidized soybean oil, respectively, during exposure to UV radiation with wavelength above 280 nm. Wood and wood coated materials photooxidation was monitored in terms of colour and structural modification as functions of irradiation time and dose. Chromatic coordinates values exhibited a slow increase with irradiation time and dose compared to the values of unmodified wood. Lignin exhibited stronger photodegradation tendencies, leading mainly to an increase of redness feature of wood samples surface. The coating layer consisting of epoxidized soybean oil protected the modified wood surface against photooxidation reactions by a screening effect. [ABSTRACT FROM AUTHOR]

Dynamic fluorination and static fluorination were applied to wood flour to decrease its hydrophilic character, aiming at processing wood-polymer composites with good properties. Fourier-Transform infrared spectra and 19 F solid state NMR (Nuclear Magnetic Resonance) results proved the successful covalent bonding of fluorine atoms onto the wood's chemical structure. It revealed that static fluorination brings about a less damaged and less hydrophilic fluorinated wood than with dynamic fluorination. Composites manufactured from this fluorinated wood presented a hydrophobic character directly related to the hydrophicity of these wood reinforcements. A composite made with fluorinated wood and polyester exhibited a higher hydrophobicity than the neat polyester and than the composite made with non-treated wood. Moreover, the further fluorination of a composite made of fluorinated wood led to a contact angle comparable to that of some metals (steel, gold) due to the etching of the composite surface during fluorination. [ABSTRACT FROM AUTHOR]

Two types of historical wood (18th century) (Juglans regia and Abies alba) presenting different degradation conditions were consolidated through acetone solutions of microcomposites consisting of a commercial polymer (Paraloid® B72) often used for wood consolidation and two different amounts (5 and 30 wt%) of microcrystalline cellulose (MCC). As a comparison, the same tests were also performed on modern samples of the same types of wood in a well preserved state. Rheological and mass variation measurements evidenced that the introduction of microfiller did not affect the viscosity and the water sorption of the neat resin to a significant extent. Moreover, mercury intrusion porosimetry highlighted how MCC filled composites were able to decrease the pore radius of treated wood samples, reaching values close to those of modern intact wood. Remarkably, the presence of MCC within Paraloid led to a positive enhancement of the stiffness and the flexural strength of treated damaged wood in both quasi-static and impact conditions, with the increase of the flexural modulus, the maximum stress and the rise of both initial and total impact absorbed energies. Additionally, an increase of the radial and tangential surface hardness due to the treatment with MCC filled composites was observed. [ABSTRACT FROM AUTHOR]

High-performance wood composite materials have attracted an increasing interest in recent years due to their excellent mechanical and thermal properties obtained by wood metallization. However, the existing methods for wood metallization generally result in structural damage to wood cell walls and large amounts of energy consumption caused by high-pressure treatment. Herein, a high-efficiency, energy-saving, self-driven wood metallization method was proposed for the fabrication of metallic wood based on high-low temperature alternating cycle treatment and the control of the moisture content in wood. The results show that a high weight percent gain of 544.65% was reached for the metallic wood with the dimensions of 20 mm × 20 mm × 20 mm. The density of the metallic wood was about 5.85 times higher than that of the unmodified wood. In addition, the compression strength and thermal conductivity of the metallic wood could be up to 3 times and 10 times higher than those of the unmodified wood, respectively. Interestingly, the penetration effect was immune to the wood sample dimensions applied here. The further mechanism analysis of the penetration of the low melting point alloy into the wood suggest that the vacuum effect in the wood channels caused by the change of water in the wood channels with the temperature difference contributed to providing the driving force and reducing the internal resistance, thus achieving rapid penetration. The modified metallic wood with enhanced physical, mechanical, and thermal properties can be potentially utilized in construction and heat-conductive flooring. ● Metallic wood has excellent mechanical, and thermal properties. ● The penetration is effected by MC, temperature difference, and cycle index. ● The net driving force analysis is innovatively applied to penetration mechanism. ● This method preserves the wood structure and don't require excess energy. [ABSTRACT FROM AUTHOR]

Biomorphic cellular C/SiC–ZrC composite ceramics were fabricated from pine and oak wood precursors. Carbonaceous preforms were first prepared by wood pyrolysis and subsequently infiltrated with polyzirconobutanediol (PZC) and polycarbosilane (PCS) to form the composite ceramics. TGA/DTG and dilatometric analysis were used to study the pyrolysis of the wood precursor. XRD and SEM analyses were applied to characterize the microscopic properties of the resulting biomorphic cellular C/SiC–ZrC composite ceramics. Compared with oak, pine was preferable for preparation of cellular C/SiC–ZrC composite ceramics because of its unique microstructure. The SiC–ZrC phase distribution differed within the composite ceramics. In addition, the compression strengths of wood, charcoal, and cellular C/SiC–ZrC composite ceramics were measured in the axis direction. Results showed the improved compression strength of biomorphic cellular C/SiC–ZrC composite ceramics when the impregnation cycles were repeated. [ABSTRACT FROM AUTHOR]

So far, no coherent and comprehensive method has been elaborated allowing investigation of skeleton furniture made of wood and wood-based materials whose components are joined by means of screws. A world furniture manufacturer whose product development headquarters are situated in Poland has become interested in the quality assessment of such furniture joints. Therefore, the objective of this research project was: elaboration of an assessment method of screw joints which connect the seat panel with the horizontal rails of the bench; determination of stiffness and strength of these joints and assessment of the impact of the kind of the applied screw connectors on bench stiffness and strength. The performed experiments revealed that the strength of screw joints depended on the total area of pressure and shear. These, in turn, depended on the screw thread diameter, number of coils as well as coil inclination angle. The elaborated method allows: an objective evaluation of the construction quality and selection of the most advantageous connection for the furniture designed in future. [ABSTRACT FROM AUTHOR]

The interest of the multi-reinforcement of wood with composite materials is investigated both experimentally and by means of simulations. 3-meter-long concrete-wood beams with and without reinforcement are designed, fabricated and tested. Only a multi-reinforcement provides interesting results concerning the ultimate behavior. Several comments and results are provided. The authors propose an analytical tool to explain these experimental aspects, based on a model of multi-layered materials involving one stress field per layer (layerwise). The static model takes cracks and delaminations into account. Criteria of crack initiations in wood thickness and along the interfaces are proposed and experimentally identified. Finally the model allows the simulation of the fracture of a concrete/reinforced wood beam in bending and/or tension. The simulations appear very close to the experimental results and highlight the potential of the concept. [ABSTRACT FROM AUTHOR]

The effects of fire retardant synergistic agents zinc borate (ZB), montmorillonite (MMT), manganese dioxide (MnO 2 ) and stannic oxide (SnO 2 ) on the mechanical properties, thermal degradation and flame retardant performance of wood flour–recycled polypropylene composites (WPC) comprised of intumescent flame retardants (IFR) were studied. The species were characterized by thermogravimetric analysis (TGA), limiting oxygen index (LOI), UL-94 tests, and cone calorimeter measurements. The results showed that the synergistic effect between IFR and ZB or MnO 2 was greater than that of MMT or SnO 2 . The addition of 5 wt% of ZB or MnO 2 , MMT and SnO 2 created fire retardant WPC with a V0 rating, exhibiting excellent fire retardancy. [ABSTRACT FROM AUTHOR]

An acoustically and structurally effective drum shell is developed for a traditional Indian drum. The basic design concept is a sandwich structure composed of carbon fibre/epoxy face sheet and balsa core on which the drum head is attached. The drum shell structure was fabricated by wet lay-up and a vacuum molding technique. Sound characteristics were analysed for both composite and wooden drums. Measured acoustical performance shows that the frequency response of the composite drum is comparable with that of a traditional wooden drum. It seems promising that composite materials with high damping characteristics could replace wooden structures used in musical instruments. Further, composite manufacturing helps in bringing standardisation and uniformity to musical instrument structures. [ABSTRACT FROM AUTHOR]