Improving Hydrophobicity of Tropical Hardwood along Axial Positions

Wood is hygroscopic and is considered dimensionally unstable materials when exposed to wet conditions. To increase the hydrophobicity of wood, this study focused on the modification of tropical hardwood (Triplochiton scleroxylon) along different positions of the stem using acetic anhydride The weight percent gain (WPG) was determined and acetylation reaction was confirmed with FTIR. The dimensional stability of the wood was characterized by water absorption (WA), volumetric swelling (VS), anti-swelling efficiency (ASE), and water repellent efficiency (WRE). Data obtained were subjected to analysis of variance at α0.05. It was observed that the weight gain (WG) by acetylation increases along the axial position (base to top) of T. scleroxylon wood. IR-spectra confirmed properly the substitution of the acetyl group. The treatment resulted in a marked improvement in the WA and VS, ASE, and WRE of acetylated T. scleroxylon wood were also found to improve considerably from base to top of the wood. It could be said that the WPG and hydrophobicity increased, but the percentage of water absorption and volumetric swelling diminished. Hence, the modified wood showed good hydrophobicity and improved dimensional stability.

Characteristics of impregnated wood by nano silica from betung bamboo leaves

Abstract, Sengon (Falcataria moluccana Miq.) as a fast-growing wood species that has low quality. Therefore, wood modification is needed to improve its wood qualities. The objective of this study was to analyse the effect of monoethylene glycol (MEG) and nano silica of betung bamboo leaves impregnation treatment on physical, mechanical properties and durability of sengon wood. 5-years-old Sengon wood from community forest, MEG and nano silica (average size = 436.16 nm) from betung bamboo leaves were used. The impregnation solutions were consisted of water treated (untreated), MEG, MEGSilika 0.5% and MEGSilika 1%. Impregnation process with 0.5 bar (60 minutes) vacuum and 2.5 bar (120 minutes) pressure. Physical properties (density and colour alteration), mechanical properties (Modulus of Elasticity (MOE), Modulus of Rupture (MOR) and hardness) and durability against subterranean (Coptotermes curvignathus) attack. The results showed that the weight percent gain (WPG) and density of treated Sengon wood were increased as the nano silica concentration increased. While colour alteration (Δε) of treated samples were declining. Mechanical properties (MOE, MOR and hardness) were also improved. Durability based on laboratory tested against subterranean attack resulted that the percentage of termite mortality from the treated samples increased, while the percentage of weight loss decreased.

Color Changes and Resistance Against Subterranean Termites Attack of Furfuryl Alcohol Impregnated Pine and Sengon Woods Through Graveyard Test

Pine (Pinus merkusii Jungh. & de Vriese) and sengon (Falcataria moluccana (Miq.) Barneby & J.W. Grimes) are common species of woods used for many purposes. Both species are known susceptible against subterranean termite attack. This study aims to analyze the effect of furfuryl alcohol impregnation on color changes and the resistance against subterranean termites of pinewood and sengon after in-ground test for one year. Furfurylated pine and sengon woods reached weight percent gain 31.2% and 79.1%, densities 0.93 g/cm3 and 0.43 g/cm3, moisture content 3.27% and 2.88%, respectively. Furfurylated pine and sengon woods have lost weight 4.07% dan 2.09%, respectively, with the average resistance level of 9.8 on both woods while untreated pine and sengon woods lost weight were 59.02% and 35.58%, with resistance level 4 and 3.8, respectively. Resistance level scoring was conducted by refering to ASTM D1758-06. Higher resistance level and lower weight loss on both furfurylated woods compared to untreated woods showed that furfurylation could increase the wood resistance against termite attack.

Physical Properties of Impregnated Ganitri Wood by Furfuryl Alcohol and Nano-SiO2

Ganitri wood (Elaeocarpus sphaericus) is a fast-growing wood that has low dimensional stability and density. This study aims were to analyze the effect of Furfuryl Alcohol (FA) and nano-SiO2 impregnation on the dimensional stability and density of ganitri wood and also examine the characteristics of impregnated ganitri wood. Impregnation used three treatments, including untreated (water), FA, and 0.5% FA-SiO2. The impregnation process was initiated by giving a 0.5 bar vacuum for 60 minutes, followed by applying a pressure of 2.5 bar for 120 minutes. Weight percent gain, leachability, anti-swelling efficiency, water uptake, bulking effect, and density were affected by the treatment. It was due to the coverage of FA and nano-SiO2 on vessels of ganitri wood (SEM analysis). Also, the presence of nano-SiO2 in wood treated (SEM-EDX analysis). FT-IR showed there were no FA bonds with ganitri wood cell wall components or between Nano- SiO2 and ganitri wood. The crystallinity of ganitri wood decreases because FA is amorphous and nano-SiO2 is semi-crystalline. The optimum dimensional stability and density were obtained at FA treatment.

In Polymerization of Environment Friendly Melamine-Urea-Glyoxal Resin in Rubber Wood for Improved Physical and Mechanical Properties

In the study, we report that a safe and simple way for upgrading inferior rubber wood through the combined modification of environment-friendly MUG resin was synthesized from glyoxal, melamine, urea, and other additives. MUG-treated wood samples were prepared with six different MUG resin concentrations (5, 15, 25, 35, 45, and 55 wt %) into the wood matrix and then heated and polymerized to form a solid and hydrophobic MUG resin in the wood scaffold, and the physico-mechanical properties were evaluated. As the MUG resin concentration increased, the weight percent gain and density increased, water uptake and leachability decreased, and the antiswelling efficiency increased at first and then decreased. MUG-treated wood sample can be prepared when the MUG resin concentration was set as 25%, and the physical properties of treated wood was optimum. Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy analysis showed that the MUG resin is widely distributed in the cell lumens and cell walls. With enhanced physico-mechanical properties, MUG-treated wood sample can be well used as a promising alternative to existing engineered wood products for structural applications.

Furfural-based resin for modifying birch wood properties

Furfural (F) cannot be easily polymerized like furfuryl alcohol, but it is an aldehyde that can react with urea (U) to make a polymeric network. The possibility of preparing F/U polymer along with an acidic catalyzer (maleic anhydride; M) was evaluated as a means to improve some selected properties of birch (Betula pendula) wood. The F+U/M resin was introduced into the wood with a double treatment technology. The first step involved dilution of F in water and methanol, and the second step was immersion in a U/M aqueous solution. The color of treated wood was darkened after resin curing from brown to a spectrum of black depending on the amount of loaded resin. The 60 to 80% of materials were converted to a non-leachable polymer based on the different formulations. The water absorption and volumetric swelling of the treated samples decreased with an increase in weight percent gain (WPG). The analysis of mechanical strength showed that treatment with F + U/M reduced to some extent the hardness and the impact bending of wood, while modulus of rupture, modulus of elasticity, and compression parallel to the grain with WPG were increased. The exposure of the samples to the accelerated weathering showed noticeable changes in color and roughness.

Thermal, Physical and Mechanical Properties of Poly(Butylene Succinate)/Kenaf Core Fibers Composites Reinforced with Esterified Lignin

In this study, Kraft lignin was esterified with phthalic anhydride and was served as reinforcing filler for poly(butylene succinate) (PBS). Composites with different ratios of PBS, lignin (L), modified lignin (ML) and kenaf core fibers (KCF) were fabricated using a compounding method. The fabricated PBS composites and its counterparts were tested for thermal, physical and mechanical properties. Weight percent gain of 4.5% after lignin modification and the FTIR spectra has confirmed the occurrence of an esterification reaction. Better thermo-mechanical properties were observed in the PBS composites reinforced with modified lignin and KCF, as higher storage modulus and loss modulus were recorded using dynamic mechanical analysis. The density of the composites fabricated ranged from 1.26 to 1.43 g/cm3. Water absorption of the composites with the addition of modified lignin is higher than that of composites with unmodified lignin. Pure PBS exhibited the highest tensile strength of 18.62 MPa. Incorporation of lignin and KCF into PBS resulted in different extents of reduction in tensile strength (15.78 to 18.60 MPa). However, PBS composite reinforced with modified lignin exhibited better tensile and flexural strength compared to its unmodified lignin counterpart. PBS composite reinforced with 30 wt% ML and 20 wt% KCF had the highest Izod impact, as fibers could diverge the cracking propagation of the matrix. The thermal conductivity value of the composites ranged from 0.0903 to 0.0983 W/mK, showing great potential as a heat insulator.

Thermal Conductivity of Poplar Wood Veneer Impregnated with Graphene/Polyvinyl Alcohol

Intending to achieve more green and economical graphene impregnated modified fast-growing poplar wood veneer for heat conduction, this study proposes and investigates the feasibility of modified veneer with graphene/Polyvinyl alcohol (Gr/PVA) impregnation mixture to improve its thermal conductivity. The absorbance and viscosity of the Gr/PVA impregnation mixtures are observed to expound the Gr/PVA ratio effects on the mixtures. Simultaneously, the weight percent gain, chromatic aberration, and thermal conductivity of the modified veneers are measured to determine the impregnation effect and the optimal impregnation formula. Further, the chemical structure, crystallinity, and thermal stability of the optimal sample impregnated with Gr/PVA are tested. The results show that the thermal properties of the Gr/PVA impregnated modified veneer have not all been improved. Still, both the dispersibility of the impregnation mixtures and the impregnation effect is affected by the Gr/PVA ratio. The data shows that the optimal thermal conductivity of modified veneer, which is up to 0.22 W·m−1·K−1 and 2.4 times the untreated one, is dipped by the mixture of 10 wt.% PVA concentration and 2 wt.% MGEIN addition. According to the characterization tests, the crystallinity of the modified veneer reduces, but the thermal stability improves.

Evaluation of water related properties of birch wood products modified with different molecular weight phenol-formaldehyde oligomers

This study investigated the effect of phenol-formaldehyde (PF) resin treatment on the dimensional stability of birch solid wood and plywood. Therefore, three different low molecular weight PF resins with average molecular weights (M w ) of 292, 528, and 884 g/mol were synthesized and used for silver birch (Betula pendula) solid wood (20 × 20 × 20 mm3) and veneer (100 × 100 × 1.4 and 300 × 300 × 1.4 mm3) impregnation to produce plywood. The weight percent gain (WPG) and bulking after curing of resin treated wood specimens were determined. The leaching was performed to evaluate the PF resin fixation stability. All tested resins at all concentrations were similarly fixed in wood blocks after the leaching (1.5–2.0% WPG loss). The dimensional stability of birch wood after treatment with all tested PF resins was significantly improved. The anti-swelling efficiency (ASE) of birch wood blocks treated with PF resins after seven water soaking-drying cycles was in the range of 39–53%, 46–65% and 49–65% using 10, 15 and 20% solution concentrations, respectively. Whereas, the ASE of plywood obtained from veneers treated with 10% of PF solution was improved by 6–20%. The equilibrium moisture content (EMC) and volumetric swelling (VS) of PF treated plywood at 98% of relative humidity (RH) decreased significantly. All PF resin treated plywood surfaces were more hydrophobic compared to untreated plywood.