Four types of industrial waste from wood processing, namely a mixed hardwood-softwood powder, pine and beech sawdust, and bark were liquefied and tested as binders for particleboards (PB) made of ...recycled wood. The liquefaction reaction was carried out at elevated temperature with a mixture of solvents from polyhydroxyl alcohols such as glycerine and propylene glycol, and
-toluenesulfonic acid as a catalyst. Then the liquefied woods (LWs) were characterized in terms of their suitability for PB production as a partial substitute for synthetic urea-formaldehyde (UF) resin. The standard properties of PBs such as tensile strength, bending strength and modulus of elasticity, density, moisture content, swelling after 24 h, water absorption, and formaldehyde content were measured. All tests were performed in comparison to a standard PB bonded by UF resin. It was demonstrated that the substitution of UF resin up to 20% of LW did not have a significant effect on the mechanical properties. PB made of recycled wood produced with LW possessed good mechanical properties that meet the European standard quality demands for PBs.
In this study, the sintering mechanism of woodceramics (WCs) from cashew nut shell waste (CNSW) was studied by analyzingchemical reactions and structural changes during the sintering process of of ...CNSW powder, liquefied wood and green bodiesof WCs at 900 oC for 60 minutes in the CO2 atmosphere. The chemical and structural properties of the products wereinvestigated by X-ray diffraction (XRD), Raman spectroscopy, Fourier Transform Infrared (FTIR), and scanning electronmicroscope (SEM). The results showed that the decomposition reactions of liquefied wood and CNSW occurred simultaneouslyto form the hard carbon and the soft carbon at high temperature. The sintering mechanism of WCs has been presented. KCI Citation Count: 0
The wood of
D. Don was liquefied in ethylene glycol (EG) with sulfuric acid (H
SO
) as a catalyst at 150°C for 60 min. The liquefied wood (LW)- and EG-based polyester polyols (EG-Poly
) were ...synthesized by reacting LW and EG with adipic acid (AA), respectively. Polyurethane (PUR) resins were made by mixing Poly
with isocyanate. The results show that LW-Poly
is a suitable raw material for PUR. The PUR films prepared with LW-Poly
have higher tensile strength with less elongation at breaking point than that with EG-Poly
. According to dynamic thermomechanical analysis, the PUR films prepared with EG-Poly
have a homogeneous molecular structure, whereas a phase separation has been found for those made with LW-Poly
. Thermal gravimetric analysis showed that the thermal degradation of LW-PUR films only starts at higher temperature than that of EG-PUR.
Epoxy resins are mostly produced from petroleum-based bisphenol A and epicholorhydrin. Bisphenol A is synthesized from non-renewable petroleum-based phenol and acetone. Biomass derived epoxy-based ...polymers (EBPs) are becoming the most promising alternative for petroleum-based counterparts, but still these biomass-based EBPs have inferior properties. In the present work, two types of epoxy resins were prepared with different weight percentages of resin (bisphenol A) and hardener. They were then modified with different weight percentages of liquefied wood from spruce sawdust. The derived EBPs were analysed in terms of tensile strength and tensile modulus, fractured surface morphology, thermal stability, long-term water adsorption and resistance to brown-rot fungus decay. The results revealed that the percentages of hardener and liquefied wood significantly influenced the overall properties of the EBPs.
•Epoxy resin was prepared with two different weight percentages of resin and crosslinking agent.•Liquefied wood-based polyol was add into epoxy resins in two different weight percentages.•The thermo-mechanical properties of new epoxy resin system was analysed using TG/DTA, DMA, SEM and tensile tester.•Biodegradation of epoxy resin was carried using Trametes versicolor.
Phenolic resin can be formed from the powder of cashew nut shell waste (CNSW), phenoland sulfuric acid. In this study, the powder of CNSW, phenol and sulfuric acid were mixed withvarious ratios in ...the reactions for formation of phenolic resin at 150oC during 180 minutes. Theformation of phenolic resin was evaluated by the non-reactive residue of CNSW, which was used tofind the best composition. The molecular mass and the separation of the constituents in the sampleswere also identified by gel permeation chromatography (GPC). The samples with optimizedcomposition were characterized molecular structures and functional groups using Fourier transforminfrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR).
We have produced hybrid liquefied-wood-based polyurethane (LW-PU) and LW-PU/nanosilica hybrid coatings for wood substrates. The prepared hybrid polyurethane coatings were hydrophobized by ...self-assembled monolayers of orthotrichlorosilane (OTS) via a sol–gel dipping process. The nanosilica addition into the LW-PU system enhanced the physical properties of coatings like surface hardness and stability toward cold liquids. The OTS hydrophobized coatings were characterized by Fourier transforms infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and thermogravimetric analysis (TGA). The surface became hydrophobic as the contact angle (CA) for the water droplet on a modified hybrid coating was ∼115° and very stable. The FTIR, SEM, and EDS analysis confirmed the formation of OTS monolayers on hybrid coatings.
In this study, wood-based activated carbon fibers (WACF) were modified by Ag nanoparticles (AgNPs) and TiO
films. The coating of TiO
films decreased the AgNPs agglomeration and exfoliation on WACF. ...As the soaking concentration of AgNO
solution (
) increased, AgNPs size and content increased, while the pore volume (especially micropore volume) of fibers reduced. However, at higher
in the range of 0.2 to0.4 mol/L, only slight variations in AgNPs content and pore structure were observable for WACF/TiO
/Ag (Ag-containing WACF coated by TiO
film). WACF/TiO
/Ag-0.1 (0.1 was the soaking concentration of AgNO
solution, mol/L) represented the best self-regeneration performance under the visible light irradiation. The self-regeneration performance of WACF/TiO
/Ag was determined by the synergistic effects of two factors: adsorption and photodegradation. The abundant pores of WACF/TiO
/Ag-0.1 increased the methylene blue (MB) concentration of TiO
surrounding and facilitated the MB photodegradation. Meanwhile, their suitable Ag content enhanced MB photodegradation. Furthermore, the principal pathway of a chemical reaction between Ag
and WACF was interpreted based on the data of surface elemental constituents and surface functional groups.
Taiwan acacia (Acacia confusa) and China fir (Cunninghamia lanceolata) were liquefied in polyethylene glycol (PEG)-glycerol cosolvent, with sulfuric acid (H₂SO₄) as a catalyst. The liquefied woods ...were blended with three kinds of isocyanate, such as poly-4,4'-diphenylmethane diisocyanate (PMDI), Desmodur L (adduct of toluene diisocyanate with trimethylol propane), and Desmodur N (trimer of hexamethylene diisocyanate), to prepare polyurethane (PU) resins. From the results, China fir had better liquefaction effect than Taiwan acacia. Those PU resins prepared from liquefied wood blending with isocyanate could cure at room temperature. Their gel property was influenced by the type of isocyanate, the molar ratio of the functional group of isocyanate to liquefied wood NCO/(OH+COOH), and the rate of catalyst added. PU resins prepared from Desmodur L had an appropriate gel time for processing. But those prepared from PMDI had too short gel time to process. Contrary, the PU resins prepared from Desmodur N would take a longer time to gel. However, addition of catalyst could shorten the gel time significantly. FT-IR analysis showed that a urethane bond had formed between the liquefied wood and isocyanate. When these PU resins were used as wood adhesives, liquefied wood blended with Desmodur L had better dry and wet bonding strength than others. Increasing the molar ratio of NCO/(OH+COOH) could increase the bonding strength. On comparing liquefied Taiwan acacia and China fir, the former had better bonding strength than the latter.
In this study, we modified melamine-formaldehyde (MF) resin adhesive with liquefied wood (LW) and determined the properties of MF-LW adhesive mixtures. Furthermore, we produced particleboards using ...prepared MF-LW mixtures and evaluated their mechanical and physical properties. Results showed that with increasing content of LW in the adhesive mixture gel time and peak temperature increased while reaction enthalpy decreased. With increasing substitution of MF resin adhesive with LW the thermal stability of adhesive mixture reduced, namely thermal degradation started at lower temperature and weight loss increased. Properties of particleboards improved with increasing amount of LW in the adhesive mixture up to 20% and then deteriorated. Nevertheless, the properties of particleboard with 30% LW in the adhesive mixture were comparable to the properties of particleboard without LW while they worsen at greater portion of LW. Consequently, MF resin adhesive with 30% LW substitution could be used to produce particleboards with suitable mechanical properties and reduced formaldehyde release content.
Liquefied wood-based polyurethane (PU) foams were made by mixing polyethylene glycol liquefied wood of Cryptomeria japonica with 4,4″-diphenylmethane diisocyanate (PMDI). Glycolysis of PU foams was ...conducted by using diethylene glycol (DEG), ethylene glycol (EG), and propylene glycol (PG) as solvent with a weight ratio of PU powders to glycol as 0.5/1, 1.0/1, and 1.5/1. The reaction was undergone at 150–190 °C for 140 min in the presence of diethanolamine (DEA) as a catalyst. The effect of reaction conditions on the efficiency of glycolysis was evaluated by the residue content, viscosity, hydroxyl value, molecular weight, and FTIR analysis of the glycolysis products. The results showed DEG, EG, and PG could be used as a solvent for glycolysis. It had the undissolved residue lower than 1%. Both transesterification and thermal decomposition simultaneously occurred during glycolysis, but the relative opportunity was depended on the weight ratio of PU powders to glycol. During glycolysis, the structure of urethane and urea in PU foams were decomposed followed by the formation of new alcohol and amine compounds. To summarize, the best suitable conditions for glycolysis of liquefied wood-based PU foams is conducted in DEG with a weight ratio of 0.5/1, and heated at 190 °C.
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