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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.

In this study, major factors involved in regulating ethanol production from wood by the saprotrophic white-rot fungus Phanerochaete sordida YK-624 were investigated. P. sordida YK-624 produced ethanol from wood meal culture without the addition of any nutrients, and ethanol was produced from wood culture only when the oxygen concentration in headspace was reduced to ≤5%; thereafter, ethanol production ceased within a few days. Analyses of gene expression during aerobic incubation indicated that P. sordida simultaneously upregulates the glycolytic pathway from sugar uptake to pyruvate conversion during ethanol fermentation and suppresses pyruvate influx into the TCA cycle. Upon termination of ethanol fermentation, the expression of all tested genes was repressed, and the fungus ceased to grow. In contrast, the fungus could utilize ethanol for aerobic growth. These results suggest that ethanol fermentation by P. sordida functions as a short-term stress response system under anaerobic conditions during wood decay, enabling the fungus to rapidly resume growing when oxygen is supplied (e.g., following breakdown of plant cell walls or removal of the fungus from water immersion). This is the first report to describe the physiologic significance of ethanol fermentation in saprotrophic white-rot fungi.

The successful isolation of DNA (Deoxyribonucleic Acid) is essential for the investigation process of forestry molecular genetics. Samples used are usually retrieved either from soft or juvenile plant organs because of their excellent DNA source. However, in certain cases, aforesaid samples are hard to obtain, as for forensic purposes. Alternatively, woods possess potential as alternative source of DNA whose extraction method has been developed with varying degrees of success. However, to date, effectiveness on tropical wood grown in Indonesia has not been widely reported. Therefore, objective of this study was to compare the results of DNA isolation of various dried and fresh wood samples by using two isolation methods: Cetyl Trimethyl Ammonium Bromide (CTAB) and Qiagen DNeasy Plant Mini Kit (QDPMK). Extraction results were visualized in agarose gels and quantified using Nanophotometer NP80 Implen which were then amplified using two universal primers: ITS and rbcL for detecting DNA signals. Extraction results from dried wood indicated no visualization in the gel, while fresh wood samples showed thick smeared bands on both extraction methods. Quantity test results denoted higher concentration in CTAB-extracted samples compared to samples extracted using QDPMK, in both types of samples, even though both resulted in optical density ratios outside the range of purity (λ260/280: 1,8–2,0 and λ260/230: 2,0, respectively). Success rates of ITS and rbcL primary amplification in dried wood samples were quite low yet outputs from the two methods did not differ significantly. Meanwhile, outcome of ITS and rbcL amplification on fresh wood samples had a fairly high success.

Hierarchically cellular, stiff, and lightweight niobium carbide (NbC)-pyrolytic carbon (PyC) monolithic foam composites possessing excellent electromagnetic interference shielding effectiveness (EMI SE) were developed via a natural wood template-based method. Pyrolytic carbon derived from the decomposed cellulose in the wood worked as the carbon source for the growth of NbC phase, and the NbC-PyC heterogeneous nano-interface formed between the residual PyC and the freshly formed NbC. Multi-loss mechanisms (e.g. conductive loss, dipole polarization loss, and especially interface polarization loss) were established by controlling the NbC content and residual PyC phase in the NbC-PyC foams, which significantly improved the absorption capability. Compared to 28.0 dB of PyC monolith, the EMI SE of NbC-PyC foam can reach 54.8 dB when the thickness is 0.5 mm, which outperforms the other porous-based shielding materials. Due to the highly porous structure of pristine wood, the resulting NbC-PyC foam exhibited a low density of 0.48 g/cm3, which is ~ 1/16 of dense NbC (7.78 g/cm3). Generally, this work introduces innovative ideas for designing novel and advanced transition metal carbide–carbon composite materials.

In this work, a biomethane fuel was obtained from biogas, using a solid matrix of ashes obtained from a central heating plant fed by wood. Biomethane composition was studied in an experimental pilot plant that treats organic waste through dry anaerobic digestion. European limits were considered and respected for the biomethane injection into the gas grid. The process was able to completely remove carbon dioxide (CO2) during its initial phase. After 50 h of test CO2 concentration started to appear in the outlet gas. This behaviour is related to the ash content, reactive phases (e.g., Ca hydroxides) and fine particle size (

Although applications of wood-plastic composites (WPC) have rapidly increased, the raw materials used for producing WPC are still sound wood until now. The decayed wood usually is discarded or used as fire wood, which causes a serious waste of resources and environmental pollution. However, the decayed wood contains high lignin content which can be used for producing polymeric materials. In this study, decayed wood plastic composites (DWPC) with nano calcium carbonate (NCC), activated carbon (AC) and chitosan (CS) were fabricated and sound wood plastic composites (SWPC) without any additive were prepared. Compared to the results of physical and chemical properties of DPWCs with SWPCs, it was found that the mechanical properties, chemical structure, thermal stability, degree of crystallinity (Cr) and flame retardancy of DWPC with CS were better than DWPC without any additive, and even better than SWPC. The addition of CS (4%) to decayed wood powder (about 30%) and PVC (about 70%) could improve the physical, chemical, and bonding properties of DWPC, which could reach the level of sound wood plastic composites. The results of this work proposed a novel green strategy for utilizing decayed wood for making polyvinyl chloride/wood flour composites.

Pure deep eutectic solvents (DESs) system of choline chloride (ChCl)/Lactic acid (Lac) were demonstrated to be an effective strategy for extraction of lignin. In this study, two kinds of different promising solid acid (SA) with DESs were designed to promote the pretreatment of lignocellulose. The SA of phosphotungstic acid (H3O40PW12) and iron bromide (FeBr3) were introduced into DESs to extract poplar wood lignin and evaluate the antioxidant activity. It was found that 82.2% and 80.9% of lignin were obtained from poplar wood under H3O40PW12-ChCl/Lac acid and FeBr3-choline ChCl/Lac system with 4 h and 8 h, respectively. The lignin fractions with a high purity (>89%), low molecular weight (Mw 1800–2000 g/mol). Besides, the antioxidant activities of lignin fractions were better than butyl hydroxyanisole (BHA). Therefore, DES lignin has prominent antioxidant activity and could developed a potential natural cosmetics and food packaging.

Carbon dioxide and hydrogen sulfide are the main contaminants in biogas, which reduce its calorific value and cause wear on metallic appliances through corrosion. There are no comparative studies on the potential of dry adsorption and wet wood ash (carbonation) process on biogas upgrade. The current study for the first time investigates the effects of different process parameters on the use of wood ash for purification of biogas and compares the performance of the two processes. The chemical composition of wood ash was characterized using X-ray fluorescence (XRF) while biogas was analysed using gas chromatography and a digital biogas analyser. The effects of process parameters on biogas carbonation method were investigated. The highest CO2 uptake and methane increment achieved by use of wood ash slurry was 2.30 mmol/g-wood ash and 88%, respectively. This high CO2 uptake was possibly due to the high content of oxides (46% TS) in natural wood ash. The optimum conditions of adsorbent/water ratio and biogas flow rate for methane enhancement were 1:4, and 100 ml/min, respectively. In dry adsorption processes, an increase in mass of activated wood ash from 2.5 to 35 g increased CO2 removal from 8.9 to 67.9%. Furthermore, the evaluation of carbonation adsorption indicated that the process followed pseudo-first order kinetics. Activation of wood ash did not significantly improve its CO2 uptake by carbonation while the uptake by activated wood through dry adsorption was comparable to that of raw wood ash through carbonation process. Conclusively, raw wood ash by carbonation process is a good candidate recommendable for purifying biogas in household digesters.

The incompatibility between wood components and polymers negatively affects the physical and mechanical properties of wood polymer composites, which is still an obstacle to fabricating wood polymer composites with desirable performance. Inspired by the good compatibilization of Janus structure, silica Janus nanosheets were synthesized by sol–gel process and used to improve the interfacial interaction of methyl methacrylate (MMA)-impregnated wood in the present study. Results showed that the Janus nanosheets with smooth convex surfaces and rough concave surfaces were successfully synthesized. The thickness of Janus nanosheets was about 30 nm, and the length could be tuned by the time of the ultrasonication. With the addition of 0.5% nanosheets, the interface gaps between the polymer and wood cell wall were remarkably decreased compared to the MMA treated wood samples, indicating the efficient interfacial interaction due to Janus nanosheets. This improved interfacial interaction was also confirmed by the changes of the pore structure of MMA/Janus nanosheets-treated wood samples. The ASE of MMA/Janus sheets-treated wood was improved by 40% compared to MMA-treated wood samples. Compared to untreated wood samples, the water uptake of MMA/Janus sheets-treated wood was reduced by 61%, while the modulus of rupture and modulus of elasticity were improved by 31% and 45%, respectively, which were higher than MMA-treated wood. Moreover, the incorporation of silica nanosheets also improve the thermal stability of the MMA treated wood sample. This preliminary research will provide a new approach for enhancing the interfacial properties of wood polymer composites.

As one of the most sustainable resources, wood has been widely used in the fields of construction, decoration, flooring and furniture. The emergence of transparent wood further expands the application fields of wood to solar cells, luminescent magnetic switches, artificial electronic skins and stress sensors. However, most of the transparent woods reported are obtained by impregnating resins such as polymethylmethacrylate (PMMA), epoxy resin (EP) and polyvinylpyrrolidone (PVP). Here, we demonstrated a flexible transparent wood prepared based on a deep eutectic solvent composed of acrylic acid and choline chloride. The light-absorbing chromophore group of natural wood was removed by the sodium chlorite delignification method to obtain the treated wood template, then the deep eutectic solvent was infiltrated into the wood template, and the final transparent wood was obtained by photo-initiated polymerization. This transparent wood has excellent stretchability (maximum tensile strain up to 73.9%), flexibility and tensile resilience. Moreover, this transparent wood also has good electrical conductivity and temperature sensing properties. The electrical signal of transparent wood has very favorable stability and repeatability in multiple heating–cooling cycles, indicating its great potential as a temperature sensor.

This paper reports a fresh and robust strategy to develop polyurethane/polysiloxane pressure-sensitive adhesives (PSAs) with excellent properties by replacing part of C5 petroleum resin with modified lignin. A unique aspect of this work is the use of renewable lignin to obtain modified monomers. The phenolic hydroxyl group of lignin is increased by 21.4% after demethylation, which will help to introduce 6-bromo-1-hexene into the lignin structure through Williamson method. The L3 lignin and C5 petroleum resin are mixed with polyurethane/polysiloxane prepolymer, and furthermore a series of PSAs are obtained under ultraviolet light. It turns out that L3 lignin can not only replace part of C5 petroleum resin, but also obtain attractive and controllable features. Especially when the mass ratio of C5 petroleum resin to L3 lignin is 6:4, compared with pure C5 petroleum resin, the 180° peel strength and the shear strength of PU46 are increased by 24.1% and 91.5% respectively. Additionally, the shear strength on the wood substrate is increased by 320.6%. This study provides an effective method for the preparation of high value-added lignin PSA, and expands the application fields of PSA.

Wood is a state-of-art, renewable, and sustainable building material with excellent mechanical properties but negligible triboelectric polarizability. Strategies to improve and rationally tune the triboelectric properties of wood are needed to further its application for mechanical energy harvesting in smart buildings. We found that wood becomes more triboelectrically positive when modified by in situ-grown zeolitic imidazolate framework-8 (ZIF-8), a metal-organic framework (MOF), and more triboelectrically negative when coated with poly(dimethylsiloxane) (PDMS). A triboelectric nanogenerator (TENG) made with two radial-cut wood samples (L x R x T: 35 x 20 x 1 mm(3)), respectively functionalized with ZIF-8 and PDMS, can generate an open-circuit voltage (Voc) of 24.3 V and a short-circuit current (Isc) of 0.32 mu A upon 50 N, 80 times higher compared with that of native wood. We demonstrate the applicability of our functionalized wood TENG (FW-TENG) in smart buildings by using it to power household lamps, calculators, and electrochromic windows. ISSN:2590-2385

Application of out-of-service rubber from a variety of sources is of both environment-protecting and resource-saving importance. To that end, recycled tire rubber was utilized as a filler to fabricate wood-high density polyethylene (HDPE) composite with enhanced toughening performance using the injection procedure in this work. Dosages of rubber powders were 0, 5, 10, and 15wt% based on the overall weight of poplar wood flour and HDPE (HDPE: wood flour = 70꞉30). The injection-fabricated composites were subjected to a four-cycle repetitive compressing loadings (0–3 kN) and dynamical mechanical analysis (DMA, room temperature to 150 ℃, in the dual cantilever mode). It was found that the rubber-filled materials exhibit advantageous energy absorption performance compared to wood-HDPE composites under repetitive compressions. The rubber-filled wood-HDPE composites are thermomechanically labile in an environment with raised temperature. The HDPE matrix substance occupies the predominant role in thermally yielding of the overall composite, typically in the temperature range of 50–75 ℃ resulting in a loss modulus peak. Up to 130–150 ℃, all the composites fully loses their moduli with loss factor (Tanδ) reaching its peak values of 0.30–0.38. To conclude, rubber-filled wood-HDPE is a qualified material applicable in proper temperature range.

This work demonstrated the promise of using industrial-grade sugar syrups derived from corn and wood, i.e., high fructose corn syrup (HFCS), glucose corn syrup (GCS) and wood-based sugar (TMP-Bio Sugar), as cheaper and competitive feedstocks for 5-HMF production using niobium phosphate as a heterogeneous solid acid catalyst in a biphasic continuous-flow tubular reactor. 5-HMF yield as high as 53.1% with 100% sugar (glucose and fructose) conversion was obtained from catalytic dehydration of HFCS-90 (containing 90 wt% fructose) at 150 °C, with feed concentration of 200 mg/ml (glucose and fructose) and aqueous to organic phase ratio of 1:5 (v/v). Catalyst stability with time was tested over 20 h of continuous-time on stream, and the reusability of the catalyst was studied after in-situ regeneration of the used catalyst by calcination in the air for removing the deposited humins and coke on the surface of the catalyst particles. The regenerated catalyst showed good activity with almost constant selectivity, although at lower glucose conversion and reduced 5-HMF yield compared to the fresh catalyst, indicating that the in-situ regeneration process could recover a part of the acid sites on the catalyst surface. The produced humins during the reaction were characterized by Fourier transform infrared spectrometry (FT-IR), thermogravimetric analysis (TGA) and elemental analysis (CHNS). The results showed high aromaticity and the presence of a high degree of unsaturated compounds in the structure of humins.

Cities in southern Chile are facing high levels of PM2.5 because of wood burning pollution. We quantify the contribution of wood smoke to fine particles in two mid-size cities: Molina and Valdivia, located in different climate zones. The sampling campaigns were carried out during austral winter (July to September) in 2018 (Molina) and 2019 (Valdivia). 24-h filter samples were analyzed for carbonaceous compounds, secondary ions, metals, and particle-phase organic molecular markers. Average winter concentrations of PM2.5 were 53 ± 32 μg/m3 (average ± standard deviation) in Molina and 89 ± 55 μg/m3 in Valdivia. The major component of fine particles was organic matter, representing more than 70% of PM2.5. Concentrations of organic molecular markers were used in a receptor model (US EPA CMB8.2) to identify and quantify primary sources of PM2.5. The major source of PM2.5 was wood smoke, which accounted for 41.55 ± 9.77 μg/m3 (62.9 ± 15.3%) in Molina and 43.65 ± 24.06 μg/m3 (51.7 ± 21.1%) in Valdivia. Secondary organic aerosols (SOA) generated from inefficient wood burning, contributed 20.4 ± 17.7% in Molina and 28.9 ± 27.6% in Valdivia. Secondary inorganic ions and dust are minor sources of PM2.5. The total contribution of wood smoke (adding primary wood smoke and SOA) could be as much as 83% in Molina and 81% in Valdivia, during the winter season.

The rapid growth of polylactic acid (PLA) production and the slow hydrolysis rate make PLA a potential environmental pollutant. In order to make better reuse of the waste PLA in energy fields and solve the potential pollutant, PLA/wood flour (WF) compounds in all different proportions were co-pyrolyzed to study the co-pyrolysis behavior in terms of energy and products. The apparent activation energy of the 50%wtWF50%wtPLA compounds during co-pyrolysis decreased by 28% than PLA and 29.4% than WF. In addition, the pyrolysis of PLA provided additional energy for the co-pyrolysis of compounds which reduced the external input energy. The chemical reactions between WF and PLA during co-pyrolysis could be called synergistic interactions which promoted the free radical reaction of PLA and lead to the increase of lactide production. The yield of the harmful acetaldehyde reduced by 85.9% in the co-pyrolysis of 25%wtWF75%wtPLA compounds. In addition, the production of small molecular benzene ring substances was increased. For example, the phenol yield increased by 31.3% in the co-pyrolysis of 25%wtWF75%wtPLA compounds. The carbon number distribution of the main products was mainly concentrated on C5–C7 which was better for the reuse of bio-fuels during co-pyrolysis.

Thermal modification reduces the hygroscopicity of timber potentially reducing susceptibility to biological degradation, but it is also energetically intensive. Identifying methods for accelerating the process could reduce these inputs. The potential effects of glycerol pretreatment on thermal modification was investigated by pre-treating poplar wood (Populus tomentosa Carr.) with 60% glycerol followed by thermal modification at temperatures between 120 and 200 °C for 4 h. Potential changes in the wood were analyzed using high performance liquid chromatography, infrared spectroscopy, X-ray diffraction, scanning electron microscopy and fluorescence microscopy to detect the changes in cell wall components, crystallinity, the average size of the crystalline region and cell wall thickness. Glycerol accelerated lignin decomposition over the entire temperature range. Thermal modification altered the degree of cellulose crystallinity as well as the average size of the crystalline region and the effects were more noticeable with the glycerol pre-treatment. The cell wall thickness of thermally treated wood decreased with increasing temperature and glycerol accelerated this process. Glycerol appears to enhance the modification process with increasing treatment temperature.

Wood-plastic composites (WPC) are actually a type of composites made by blending wood particles/flour with polymers. The Mechanical Properties of Wood Plastic Composites primarily is dependent on the makeup of the matrix of its (Polymers), reinforcements (Sawdust), coupling agents, and lubricants. In general, the polymer of the matrix in WPCs is actually made of a single monomer like HDPE, PS, PP, PET, etc. The Objective of the project is actually investigating the physical properties of a Wood Plastic Composite by using polymer blend (a combination of two or maybe more polymer) as a matrix and the effects of its own physical properties of WPC by varying the makeup of the combination at various proportions.

Because of the smooth, dense, and nonpolar surface of wood-plastic composites (WPCs), it is challenging to form an efficient bonding interface between the WPC and the material of the wood veneer by using traditional adhesives. In this study, two kinds of silane coupling agents (r-aminopropyl triethoxy silane, production number KH550; and trimethoxy vinyl silane, production number A171) and dicumyl peroxide were used to improve the bond between the wood fiber/high-density polyethylene (WF/HDPE) composite and the wood veneer. The attenuated total reflection-Fourier transform infrared spectroscopy curve shows that the two kinds of silane coupling agents were grafted to the surface of the wood veneer, and the contact angle between distilled water and the veneer surface increased from 46° to greater than 120° after treatment. The bonding strength between the treated veneer and the WF/HDPE composite was significantly enhanced, and samples treated with A171 had higher bonding strength than those treated with KH550. The greater the volume of wood fiber in the WF/HDPE, the poorer the bonding strength of the veneer and the lower its water resistance. Images from a scanning electron microscope show that the silane coupling agent A171 can induce a denser interface between the wood veneer and the WF/HDPE composite.

The aim of the present work is to provide a preliminary support and research foundation for developing integrated technology of methane dry reforming and pine wood pyrolysis to produce high value chemicals and fuels. The chemical properties of bio-oil produced by pine wood pyrolysis under traditional N2, H2, CO2, CH4 atmospheres and mixtures of CH4 and CO2 were investigated. Experimental studies were conducted in a fixed bed reactor at a temperature of 500 °C. The results show that pine wood pyrolysis under mixtures of methane and CO2 can promote bio-oil production (0.98% increase) compared with traditional pyrolysis (under N2). GC-MS results show that the contents of phenols and sugars in bio-oil decreased, while the amount of alcohols, aldehydes, ketones, and furans increased. NMR spectroscopy provides additional support of the results. Results indicate that bio-oil can be used as a source of value-added chemicals. High proportions of CO were obtained in the gas products from pine wood pyrolysis under CH4 and mixtures of CH4 and CO2. Finally, a possible reaction pathway of pine wood pyrolysis under mixtures of methane and CO2 is proposed. Methane bi-reforming with CO2 and steam from pine wood pyrolysis could promote the production of high value oxygen-containing chemicals during pine wood pyrolysis under mixtures of CH4 and CO2.

The development and performance in practice of a commercial automatically controlled wood stove is described. The digital control system controls the three combustion air inlets individually, based on the combustion phase, measured flue gas temperature, measured O2 outlet concentration and desired room temperature. The control system ensured a well-controlled combustion cycle with respect to temperature and oxygen concentration, yielding improved thermal efficiency and minimized carbon monoxide emissions. A minimum in CO emissions was identified for the oxygen operation range 10–13% O2. The improved performance has been verified by field tests in 5 private homes, demonstrating more stable and optimal O2 concentrations and temperatures compared to manual operation. This resulted in significant lower CO concentrations (up to 27%) alongside higher thermal efficiency (up to 20%) when comparing manually and automatically controlled wood stoves. This new technology has a great potential for improving the stove efficiency/biomass utilisation and reducing the emissions of pollutants at low altitude close to private homes.

This paper presents a novel development of sludge cellulose plastic composite (SPC) in line with the circular economy concept by using recovered sludge cellulose from wastewater treatment plant (WWTP). Bearing the aim of replacing the wood in wood plastic composite (WPC) with sludge cellulose, WPC was developed in parallel for determining the substitution potentials. In order to maximise the integration of properties, maleic anhydride (MA) and vinyltrimethoxysilane (VTMS) coupling agents were employed to refine the interfacial bonding of both SPC and WPC. In line with the main aim of circular economy – to decouple the economic value from the environmental impact, eco-efficiency analysis was performed for the developed process. The results showed that the tensile and flexural strength of the composites were substantially enhanced after both treatments, while MA appeared to be more efficient than VTMS in the refinery of interfacial bonding. Scanning electron microscope (SEM) analysis confirmed the improvement of interface by identifying well embedded and firmly bonded wood flour or sludge cellulose in the matrix. WPC was marginally more thermally stable than SPC, while SPC suggested comparable flexural properties. Eco-efficiency assessment results showed that the SPC had better environmental and economic performance than the WPC. The latter turns sludge cellulose as a promising sustainable alternative to wood or natural fibres in the production of WPC.

In this work, twenty-five kinds of choline chloride (ChCl)-based deep eutectic solvents (DESs) containing acid, hydroxyl, amide, and binary hydrogen bond donors (HBDs) were prepared and successfully used to pretreat pine wood powder. As a result of the pretreatment, the glucan content in the pretreated biomass was increased, whereas the contents of hemicellulose and lignin were significantly decreased. The biomass pretreatment efficiency of the DESs had improved with increasing the polarity and hydrogen bond acidity (α) of the DESs. Among the studied DESs, ChCl:lactic acid:formic acid (1:1:1) with the highest α value was the most efficient DES in extracting lignin from biomass. The pretreated biomass also showed an enhanced enzymatic saccharification yield owing to the decreased particle size of the biomass and reduced content of hemicellulose and lignin. During the pretreatment process of biomass using DESs, the extracted lignin could be recovered successfully, with a yield of up to 60% and purity of over 90%. The molecular weight of the extracted lignin was much lower than that of the native cellulolytic enzyme lignin. The DES used for pretreatment process could be also successfully reused with high recovery yield of DES and high retention of delignification capacity.

Using NaOH/ urea solution to partially dissolve wood flour, a novel nano-TiO2 photocatalytic composite was prepared by hydrothermal method with insoluble wood flour as bio-carrier and dissolved components of wood flour as accelerant. SEM results showed that the control sample prepared without adding titanium sulfate consisted of insoluble wood flour and still possessed unbroken fibers after hydrothermal treatment. The control sample prepared without wood flour addition was only composed of TiO2 micro-particles. With assistant of the dissolve components of wood flour, nano-TiO2 with the size of 50−300 nm was well assembled on the surface of insoluble wood flour. The composite is composed of anatase TiO2 and insoluble wood flour and possess high specific surface area. The absorption edge of composite extended to the visible light range. The composite exhibited high removal rate of methylene blue, up to 97.7% within 120 min. This performance was even better than commercial TiO2 (P25) with the rate of 81.8%. The reused performance of the composite retains removal rate of 90.7% even after 5 cycles. The environment-friendly nano-TiO2 photocatalytic composite can be very useful for degrading refractory organic pollutants.

This work investigated the influence of processing parameters on properties of geopolymers based on wood biomass fly ash. Five curing methods were applied, with and without moisture and temperature control, associated with 2 concentrations of alkali activators, sodium silicate and sodium hydroxide (1.0 and 1.5 weight ratios), and a fixed composition (75 wt.% wood biomass fly ash and 25 wt.% metakaolin). Cured geopolymers were characterized by compressive strength tests after 28 days and by analytical techniques to evaluate morphology and internal structure. The results showed different physical and chemical properties tailored by the processing parameters variation, suggesting several applications. For instance, the samples obtained with hydrothermal conditions and SS:SH = 1.0 might be used for adsorption of pollutants, and those produced at room condition with SS:SH = 1.5 may be employed as dense mortars. Most importantly, a low-energy curing method at room temperature enabled to produce geopolymers with mechanical properties in the order of magnitude of those obtained at higher times or temperatures.

Combustion and oxy-fuel combustion characteristics of torrefied pine wood chips were investigated by Thermogravimetric Analysis (TGA). Three torrefaction temperatures (250, 300, and 350 degrees C) and two residence times (15 and 30 min) were considered. Experiments were carried out at three heating rates of 10, 20, and 40 degrees C/min. the isoconversional kinetic methods of FWO, KAS, and Friedman were employed to estimate the activation energies. the assessment of uncertainty in obtaining the activation energy values was also considered. the obtained results indicated that due to torrefaction, the O/C and H/C atomic ratios decreased, resulting the 300 degrees C-30 min and 350 degrees C-15 min torrefied biomass to be completely embedded in lignite region in van-Krevelen's diagram. Oxy-fuel combustion affected the decomposition of cellulose and lignin components of biomass while the impact on the hemicellulose component was negligible. the kinetic analysis revealed that with the evolution of conversion degree, the activation energy values increased during hemicellulose degradation, remained approximately constant during cellulose decomposition and showed a sharp decrease for lignin decomposition. the activation energy trends were comparable in both air and oxy-fuel combustion conditions, however slight changes in activation energy values were noticed. the highest activation energy value was obtained for 250 degrees C-30 min torrefied biomass at 183.40 kJ/mol and the lowest value was 72.93 kJ/mol for 350 degrees C-15 min biomass. the uncertainty values related to FWO method were lower than KAS and Friedman methods. the uncertainty values for FWO and KAS methods were at the range of 5-15%. (C) 2019 Energy Institute. Published by Elsevier Ltd. All rights reserved., [TUBITAK-1003]; [213M525], The financial support for this work by TUBITAK-1003 under Grant 213M525 is greatly appreciated. the views expressed in this paper belong to authors.

Enhancing the performance of starch-based wood adhesive is vitally important for its practical applications. Accordingly, we designed the use of micronized starch (MS) to prepare micronized starch-based wood adhesive (MSWA) by incorporating 0, 2, 4 and 6% (w/w, dry basis starch) sodium dodecyl sulfate (SDS). The results showed that 2% SDS exhibited remarkable improvement in shear strength and viscosity of MSWA. The grafted reaction was demonstrated by 1H NMR and the steady shear results indicated that the adhesive possessed a pseudoplastic behavior under yield stress conditions. Besides, dynamic rheological measurements were applied to evaluate the structure of MSWA under varying frequencies, temperatures and constant stain. The transmission electron microscopy (TEM), Zeta potential and surface tension indicated that SDS could improve the surficial properties. Meanwhile, the microstructure of adhesive films and fracture surfaces of glued wood veneers by scanning electron microscopy (SEM) demonstrated that the migration of SDS led to the formation of surfactant layer. Furthermore, element analysis revealed the distribution of S/N in latex slices. The results of this study provide the detailed information about the influence of SDS on the rheological properties and microstructures of MSWA, which may facilitate the preparation of high performance bio-based adhesive for wood applications.

Protic ionic liquids have been proposed as effective solvents for the selective extraction of lignin from wood. In this work, the protic ionic liquid 1-methylimidazolium chloride has been used to extract lignin at different biomass loadings, temperatures, and times to understand the influence of treatment severity on the lignin dissolution mechanism. The maximum lignin recovery (82.35 g lignin/100 g biomass lignin) was achieved at 10% (w/w) biomass loading, 135 °C, and 6 h. An increase in treatment severity leads to an acid cleavage of ether linkages, which increases the average molecular weight and thermal stability of lignins due to C-C repolymerization. HSQC-NMR analysis showed the effect of operating conditions on the predominant mechanism of lignin depolymerization. At mild conditions, there is a preferential degradation of G units (the typical depolymerization mechanism of ionic liquid treatments); but at the most severe conditions, S units are predominantly removed, as usually occurs in acidic treatments. This work contributes to better understanding the different lignin extraction mechanisms occurring with a protic ionic liquid depending on different operating conditions.

The natural durability of five Cameroonians wood samples was evaluated using the European standard EN 350-1 with a slight modification. The capacity of extracts to inhibit the fungal growth was evaluated at different concentrations with propiconazole (a commercial fungicide for wood) as standard. Scanning Electron Microscopy (SEM) of wood blocks was carried out before and after extraction in different solvents. Unextracted and extracted wood blocks were exposed to fungal attack, with beech as a reference wood. Results showed that mass losses of non-extracted samples ranged from 0.1 to 59% and those of extracted samples from 3% to 40%. Before extraction, all wood samples under study were classified as very resistant to fungi attack (class 1) with respect to the standard. After extraction, some of the wood samples became vulnerable to fungal attack. Movingui, padouk, and tali became less resistant to fungi attack (class 3). The SEM of wood revealed that the extractives were removed from the fibres. The effect of extractives on fungal growth showed that extracts weakly inhibited fungal growth up to concentrations of 250 μg/mL but extracts of tali and movingui totally inhibited fungal growth at a concentration of 500 μg/mL.

The aim of this research is investigating the thermal properties of wood-plastic composites (WPCs) as flat panels. The study has included many properties such as: thermal conductivity, thermal stability, thermal expansion and melting point. The WPCs are composite materials made of high-density polyethylene (HDPE) and polypropylene (PP) incorporated with wood flour taken from pine trees. The concentrations of wood in the composites are (10, 20 or 30 %). The work has done experimentally by manufacturing the specimens and measuring the thermal properties. The results show that the addition of 10% wood, to the composite, leads to reduce the thermal conductivity of WPC by 4-10%, reduce the thermal expansion by 8-12%, and to increase the melting point by (2-3°C) for both HDPE and PP wood composites. It has found also that wood could be used with plastics that have low melting points, or below the degradation temperature of wood (such as: HDPE, LDPE, PP, PVDF and PA) to ensure less mass loss and more thermal stability.

Small scale gasification of Solid Recovered Fuels (SRF) in downdraft reactors could be an alternative to large scale waste-to-energy schemes. In this perspective, the assessment of the pollutant emissions at pilot scale is necessary. This work compares pollutant emissions from wood and SRF air gasification in a downdraft fixed bed gasifier. Five fuels have been studied: Poplar wood, SRF wood, and three different mixtures containing mass fractions of 80% SRF wood with 20% of either tire, plastic waste or sewage sludge. Air gasification was performed in a pilot scale reactor in fed-batch mode using a fuel mass ranging from 5 to 8 kg and an air inlet flow of 170–180 L min−1 (at 0 °C and 101 325 Pa). Depending on the fuel, Equivalence Ratios (ER) ranged from 0.22 to 0.29 and gasification temperatures from 690 to 850 °C. Emissions analyses were performed on product gas, condensable species and remaining chars, with a particular focus on sulfur, nitrogen and heavy metals. Regarding sulfur, wood and SRF wood led to low H2S contents (6–8 μmol mol−1), when SRF mixes led to higher concentrations (44–96 μmol mol−1) in addition to of up to 11 heavier sulfur compounds. Regarding nitrogen, SRF produced higher ammonia concentrations (2.1–7.6 mmol mol−1) than Wood (619 μmol mol−1), as a result of initial nitrogen mass fractions17 to 27 times higher in the SRF mixes. Heavy metals analyzed in remaining solids after gasification showed low recovery rates (< 0.4%), and tend to accumulate in fine particles, as a result of their volatility.

The bondline chromatic alteration of poly(vinyl acetate) (PVAc) in wood assemblies has an appreciable impact on the aesthetic characteristic of these products (mostly important for panels used in furniture). While the origin of this phenomenon has been explained for the cases of pure polymers and wood substrates alone, present work investigates about the origin of discoloration for the case of bondlines prepared with selected wood species (cherry and maple) and two commercial PVAc dispersions, one containing and one not containing aluminum ions. Assemblies were exposed to temperature and UV light. The comparison (carried out through GC-MS analysis) among the compounds extracted by these species before and after exposure allowed identifying specific flavonoids that were used as model-compounds to replicate the discoloration process in laboratory. Thus, using spectrophotometric measurements and TLC analysis it is shown that discoloration is related to the presence of aluminum in the dispersion, whose interaction with flavonoids in wood generates different forms of complexes that can be modified upon irradiation and emitting in the visible range. Although the specific involved compounds are species-related, it can be suggested that the identified mechanism at the basis of discoloration in PVAc-wood bondlines has general validity.

Fossilized wood belongs to the most exciting, however, rarely studied objects in nature. Several kinds of petrified wood with different combinations of minerals have been studied: apatite – calcite; calcite – pyrite; hematite – gypsum wood; quartz - goethite; goethite – calcite woods, from different countries and estimated as old in the time range of 1.8–306 MA. The samples cover nearly the whole time of tree existence on the Earth. The application of synchrotron radiation for X-ray microdiffraction analysis of petrified wood is presented and compared to elemental (electron microprobe) and molecular (micro Raman) analyses with the use of table-top instruments. The analysis of preserved cells permineralized with two minerals allows tracing both the structure of cell walls and the remains of ancient organic matter. Lignin is most often met among the remains of the primary organic matter and is clearly observed in all kinds of wood, except the apatite-calcite one. The Eh-pH diagrams tailored to each combination of minerals with organic matter allow to estimate the original conditions of mineralization and give the indications for the potential biomimetic synthesis.

Wood dust is one of the most common occupational exposures, with about 3.6 million of workers in the wood industry in Europe. Wood particles can deposit in the nose and the respiratory tract and cause adverse health effects. Occupational exposure to wood dust has been associated with malignant tumors of the nasal cavity and paranasal sinuses. The induction of oxidative stress and the generation of reactive oxygen species through activation of inflammatory cells could have a role in the carcinogenicity of respirable wood dust. Therefore, we conducted a cross-sectional study to evaluate the prevalence of urinary 15-F2t isoprostane (15-F2t-IsoP), a biomarker of oxidative stress and peroxidation of lipids, in 123 wood workers compared to 57 unexposed controls living in Tuscany region, Italy. 15-F2t-IsoP generation was measured by ELISA. The main result of the present study showed that a statistically significant excess of this biomarker occurred in the workers exposed to 1.48 mg/m3 of airborne wood dust with respect to the unexposed controls. The overall mean ratio (MR) between the workers exposed to wood dust and the controls was 1.36, 95% Confidence Interval (C.I.) 1.18–1.57, after correction for age and smoking habits. A significant increment of 15-F2t-IsoP (43%) was observed in the smokers as compared to the non-smokers. The urinary excretion of 15-F2t-IsoP was significantly associated with co-exposure to organic solvents, i.e., MR of 1.41, 95% C.I. 1.17–1.70, after adjustment for age and smoking habits. A 41% excess was observed in long-term wood workers, 95% C.I. 1.14–1.75. Multivariate regression analysis showed that the level of 15-F2t-IsoP was linearly correlated to the length of exposure, regression coefficient (β) = 0.244 ± 0.002 (SE). The overall increment by exposure group persisted after stratification for smoking habits. For instance, in smokers, a 53% excess was detected in the wood workers as compared to the controls, 95% C.I. 1.23–1.91. Our data support the hypothesis that oxidative stress and lipid peroxidation can have a role in the toxicity of wood dust F2-IsoP measure can be a tool for the evaluation of the effectiveness of targeted interventions aimed to reduce exposures to environmental carcinogens.

In the present work, palm wood was pretreated using hydrothermal technique in conjunction with chemical method for removal of lignin. Pretreated palm wood was subjected to hydrolysis using Trichoderma reesei MTCC 4876. Subsequently bioethanol was produced using palm wood hydrolysate by Kluveromyces marxianus MTCC 1389. RSM was used to identify the non-linear relationship and optimize various process parameters such as parameters such as pH, temperature, agitation rate, substrate concentration and inoculum size for bioethanol production. ANN constructed with 5-2-1 topology was also used to optimize process parameters. The experimental bioethanol yield of 22.90 g/l was obtained at ANN optimum conditions of temperature 45 degrees C, agitation rate 156 rpm, pH 5, substrate concentration 8% (v/v) and inoculum size 3.2% (v/v).

Novel bio-inspired materials derived from crystalline nanocellulose (CNC) have been tested as wood consolidants. A suspension of CNC, produced by acid hydrolysis of cellulose and used as such or mixed with lignin and/or siloxane derivatives (PDMS), was applied on rotted wood samples of Norway spruce. X-Ray diffraction analysis on CNC powder showed high crystallinity index. Dynamic light scattering (DLS) measurement indicated a nearly uniform particle size distribution with an average hydrodynamic diameter for pure CNC smaller than that in the mixtures. Raman and FTIR spectroscopies suggested interactions between lignin, PDMS and CNC components. The storage modulus of wood samples, measured by Dynamic Mechanical Analysis on the same specimen before and after consolidation, confirmed the efficiency of pure CNC, which displayed a considerable improvement of stiffness. A substantial increase of E’ was observed particularly for most decayed classes. These results suggest a closer interaction between nanocellulose and decayed wood.

Wood-derived carbons have been demonstrated to have large specific capacities as the anode materials of lithium-ion batteries (LIBs). However, these carbons generally show low tap density and minor volumetric capacity because of high specific surface area and pore volume. Combination with metal oxide is one of the expected methods to alleviate the obstacles of wood-derived carbons. In this work, the composites of MnO loaded wood-derived carbon fibers (CF@MnO) were prepared via a simple and environmentally friendly method, showing decreased specific surface area due to the generation of MnO nanoparticles on carbon fibers. Furthermore, the CF@MnO compostites exhibit superior electrochemical performance as anode materials of LIBs, which show high reversible capacity in the range of 529–734 mAh/g at a current density of 100 mA/g. The optimal CF@MnO product (MnO:carbon = 1:2) delivers reversible capacity of 734 and 265.3 mAh/g at current density of 100 and 2000 mA/g, respectively. Besides, the material presents outstanding stability with coulombic efficiency around 100% after 200 cycles at a high current density of 400 mA/g, revealing a potential as promising anode materials for high-performance LIBs.

The article presents the results of mathematical modeling of the initial stage of the combustion of wood and coal particles in conditions corresponding to the combustion chambers of boiler units of thermal power plants. A hypothesis is formulated that describes the sequestration of anthropogenic sulfur oxides (SOx) under the conditions of combustion of mixed fuels based on coal and wood as a result of the interaction of water vapors (formed during the evaporation of interporeal and adsorbed biomass moisture) with SOx with the formation of sulfuric (H2SO4) acid vapors. When these vapors of sulfuric acid H2SO4 interact with iron oxides of the mineral part of the coal. To test the formulated hypothesis, a new mathematical model has been developed for the processes of co-ignition and combustion of wood and coal particles under high-temperature heating conditions. The mathematical model of the ignition process developed by the authors differs from the known ones (published in leading international scientific periodicals on the combustion of solid fuels) by a detailed description of a complex of gas-phase and heterogeneous thermochemical reactions occurring both in the boundary layer of fuel particles and in their porous structure. The mathematical model of the combustion process of wood-coal fuel particles developed by the authors is currently the most detailed in describing the thermophysical, thermochemical and aeromechanical processes occurring both in the fuel particles and in their small vicinity. Multistage kinetic schemes for the oxidation of the main volatile components (methane ‒ CH4, carbon monoxide ‒ CO, hydrogen ‒ H2), as well as the formation of sulfur oxides by means of oxidation of hydrogen sulphide (H2S), released as a result of pyrolysis of the organic part of coal, have been adopted. Based on the results of numerical modeling, the possibility of intensifying the processes of sequestration of sulfur oxides by moistening the wood component of the fuel mixture has been established. It is shown that water vapor can act as an agent adsorbing anthropogenic sulfur oxides, transforming the latter into sulfuric acid vapor, respectively. In turn, the vapors H2SO4 and HNO- 3 can be relatively easily captured by means of condensation. It has been established that for effective SOx capture during co-combustion of coal and biomass, the moisture content of the latter must be at least 5% by weight. The research provides grounds for the conclusion about the possibility of environmentally efficient combustion of coal in the composition of wood-coal fuel composites.

As a green and sustainable natural resource, wood is regarded as a feasible candidate material for developing green and sustainable energy due to its natural porous structure. However, the conductivity of wood is poor, which restricts its application in energy storage. In this research, a novel material with Li–Na metal compounds inserted into porous carbonized lignin free wood (PCLFW) as a bifunctional hybrid is synthesized. This material with a high specific capacitance, high power density and excellent electrocatalytic activity is synthesized. The final product shows a high specific capacitance of 255 F g−1, high energy density of 31.88 Wh kg−1 and power density of 3188 W kg−1. Moreover, after experiencing 5000 cycles, the specific capacitance is maintained at 239 F g−1 (capacitance retention of 93%). In addition, the hybrid exhibits excellent hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) activities in alkaline solution, with overpotentials of 349 mV (Tafel = 192 mV dec−1) and 484 mV (Tafel = 184 mV dec−1), respectively. Meanwhile, the hybrid also shows a larger initial and half-wave potentials of −0.12 V and −0.22 V, reflecting an outstanding oxidation-reduction reaction (ORR) property. In a word, this work provides a new idea for us to fabricate wood-based hybrid for high-performance energy storage devices and carbon-based catalysts.

Wood flour (WF) filled polymer composites are widely used in our daily life. Unfortunately, a wick effect of WF during burning seriously deteriorates the flame retardancy of wood-plastic composites. Traditional flame retardants cannot efficiently restrict the wick effect of WF due to their random distribution. In this work, amino glycerin decorated ammonium polyphosphate (APD-APP) was well designed and prepared through an ion exchange reaction to tailor the dispersion of flame retardant in WF-filled polymer composites. When the APD-APP was incorporated into the WF/polypropylene composite (WPC), it showed significantly different distribution compared to that of APP and mainly accumulated at the surface of WF, and then resulted in the formation of core-shell WF@APD-APP. More importantly, the flame retardancy of WPC/APD-APP is remarkably superior to that of WPC/APP. In vertical burning test, 25.0 wt% of APD-APP upgraded the UL-94 rating and limiting oxygen index (LOI) of WPC from no rating and 19.0% to the corresponding V-0 rating and 29.0%. Moreover, the melt dripping of WPC was completely eliminated by APD-APP. In the combustion test, the peak of heat release rate and total smoke production for WPC were respectively decreased by 70.0% and 76.6% in the presence of 30.0 wt% of APD-APP. In addition, mechanical properties of WPC/APD-APP are also superior to that of WPC/APP. The mechanism for the excellent flame retardancy of WPC/APD-APP revealed that the formed core-shell WF@APD-APP affected a residual network through the intergrowth charring of APD-APP and WF during thermally decomposing, and then the wick effect of WF was significantly weakened. Finally, the flame retardancy of WPC/APD-APP was enhanced through typical intumescent flame-retarding action via simultaneous interfacial and bulk charring.

Wood-based biochar, as a metal-free heterogeneous activator of peroxydisulfate (PDS), was successfully prepared by pyrolysis of polar sawdust for efficient removal of Acid Orange 7 (AO7). The results demonstrate PDS could be effectively activated by wood-based biochar, and AO7 was rapidly eliminated in a wide range of pH value (3.0–10.0) with AO7 removal achieved ≥ 99.3% after 14 min reaction. The dominant reactive species in the biochar/PDS system were verified via radical quenching tests and electron paramagnetic resonance (EPR) technique. It is speculated that sulfate radicals (SO4•−) and hydroxyl radicals (•OH) were formed on the surface of biochar. Based on the results of X-ray photoelectron spectroscopy (XPS), π-electron density and oxygen-containing functional groups (especially C–OH) on biochar surface were active centers for the catalytic reaction. Recycle experiments of biochar for 4 runs were carried out and the regeneration method of the catalyst was also studied.

Fatigue analysis and fatigue reliability of polypropylene (PP)/wood flour (WF) composites were studied. The composites were prepared by incorporating wood flour with and without maleic anhydride and peroxide (MAPO) into cellulose nanofibres impregnated polypropylene. The prepared composites were then characterized by tensile and fatigue analyses. The tensile strength and fatigue life of MAPO mixed composites were lower compared with the composites without MAPO. It was also found that the fatigue experimental data of the composites were widely scattered regardless of the type of composites. Hence, in this study, a fatigue reliability of the composites was sought. Based on the fatigue experimental data, 95% confidence band were created. Since 95% confidence lower band ensure 95% survivability and only 5% failure of the composites, hence, from this study, it is suggested that the fatigue life obtained from 95% confidence lower band can be used as a material reliability index for safe fatigue design of the composites. Keywords: Melt-viscosity, Wood plastic composite (WPC), Fatigue behavior, Wood flour, Polypropylene

The co-gasification of beech-wood and polyethylene has been investigated in a lab-scale fluidised-bed reactor in the presence of four different types of bed materials (silica sand, olivine, Na-Y zeolite and ZSM-5 zeolite). ZSM-5 zeolite is very effective as a catalytic bed material in fluidized-bed reactor for wood-only gasification and co-gasification in terms of high hydrogen production and CGE. Na-Y zeolite is more effective compared with ZSM-5 zeolite in co-gasification of the beech-wood and polyethylene process. The catalytic activity in co-gasification of beech-wood and polyethylene can be ranked accordingly: Na-Y zeolite > ZSM-5 zeolite > olivine. In general, higher amounts of steam injected in the fluidized-bed reactor and more polyethylene would lead to higher hydrogen production in the co-gasification process.

In this study, it was investigated the feasibility of wood-plastic composites (WPCs) made of polylactic acid (PLA), as a biobased thermoplastic matrix material and treated wood flour (Pinus sylestris L.) with Tanalith E, as organic reinforcement of matrix material. The wood flour amounts in composites were 30, 40 and 50 wt% by weight fiber loadings. Maleic anhydrid grafted polyethylene (MAPE) as a coupling agent was also used to improve the compatibility between the fiber and plastic matrix. Density, void content, water absorption, thickness swelling, tensile test, flexural properties, impact strengths, thermal properties, microstructural and morphological characterization and durability against white rot (Trametes versicolor (MAD-697) (L:Fr.) Pilat) and brown rot (Coniophora puteana ((Schumach.: Fr.) P. Karst (Mad-15)) were used to characterize the WPCs properties. Results revealed that WPCs with untreated wood flour had higher densities compared to those of WPCs with treated wood flour for the same wood contents due to higher void content of treated wood flour-PLA composites. In addition, water absorption and thickness swelling rate of WPCs increased with an increasing the fiber content in WPCs. Regarding to mechanical properties, PLA composites with treated wood flour content of 40 wt% showed best mechanical performance among the different fiber contents. The percentage of weight loss and residual ratio increased with increases in both the wood flour content and the temperature. All tested WPCs had lower weight losses than that of control (untreated wood) samples due to encapsulation of wood by biobased thermoplastic matrix.

A kinetic study of the delignification of cedar wood during organosolv treatment using 1-butanol was conducted. The results revealed that the primary particles in the delignification were not wood chips, but the tracheid cell wall in the wood structure. In addition, the delignification proceeded from the lumen of the tracheid cell wall into the middle lamella, which suggests that the kinetic situation was similar to that in the unreacted-core model. The amount of delignification increased with reaction time, although the cellulose remained a solid with mesopores. These results indicate that delignification should proceed to produce pure cellulose layers. Therefore, delignification was analyzed using the unreacted-core model, which revealed that the rate-determining step was the diffusion of dissolved lignin molecules within the cellulose layer. The mesopore and lignin particle size were approximately 3–10 nm and 2.7–5.4 nm, respectively. This size relation predicted that the diffusion rate would be very low, which supported the result from the unreacted-core model analyses. Finally, the effective diffusion coefficient was calculated from unreacted-core model equations, and produced a value of 4.09 × 10−19 m2 s−1, which was low and indicated that diffusion of the lignin molecules within the cellulose layer was the rate-determining step.

Cell wall components and structure impact the physical and mechanical properties of plants, thereby affecting wood applications. Lignin is the most abundant biopolymer after cellulose in the wood cell wall and can be modified by certain lignin biosynthesis enzymes. 4-Coumarate: coenzyme A ligase(4CL) is an important lignin biosynthesis enzyme. To demonstrate the impact of the regulation of Pto4CL1 from poplar on wood properties, we analyzed the composition and anatomy of 5-year-old Pto4CL1-modified poplar cell walls, assessing the density, strength, volume shrinkage, and impact toughness of the transgenic trees. These results showed that the up-regulation of Pto4CL1 increased the lignin content to 46.65% from 33.11% in the control plants, while hydrophilic polysaccharides such as cellulose, hemi-cellulose, and pectin decreased. In contrast, the down-regulation of Pto4CL1 resulted in a reduction in lignin content to 27.39%, and the content of cellulose and hemi-cellulose showed compensatory variation. Raman spectroscopy showed that the change in lignin in the transgenic events was embodied in the deposition and concentration of lignin in the secondary cell wall. Moreover, the increased lignin content caused significantly increased wood strength and slightly increased wood density. In contrast, a reduction in lignin content resulted in a significant decrease in wood strength and a slight decrease in wood density. However, the Pto4CL1-modified trees had similar stiffness to the control group. We also found a significant decrease in volume shrinkage and increase in impact toughness in the low-lignin events. These results indicate that Pto4CL1 regulation alters the chemical composition of plant cell walls and these changes affect the physical and mechanical properties of the wood.

Dyeing of solid wood using scCO2 as transport medium does not afford satisfying results as exemplarily demonstrated for disperse blue 134 and different wood species. Surprisingly, the bark of cork oak featuring closed porous architecture could be easily dyed with DB 134 which was hypothesized to be caused by the high content of lipophilic moieties in the suberin-rich thin walls separating the individual cells. To verify that non-polar constituents and their plasticization play a key role for diffusion of dye-loaded CO2, we impregnated wood samples with lipophilic alkyl ketene dimer (AKD) and confirmed its presence in the interior by FT-IR and water contact angle measurements. The results of subsequent scCO2-assisted dyeing confirmed that deposition of the common paper-sizing agent AKD on the internal surface of the wood samples significantly improved dyeing with DB 134 as evident from CIELAB colour space measurements.

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.