Seng Hua Lee

Chemical, physico-mechanical properties and biological durability of rubberwood particleboards after post heat-treatment in palm oil

Abstract The chemical properties, dimensional stability, mechanical strength and termite resistance of urea formaldehyde (UF) bond rubberwood (RW) particleboard (PB) were assessed after a two-step oil heat treatment (OHT). The PB was immersed in palm oil before heating to 180, 200, and 220°C in a laboratory oven for 2 h. Anti-swelling efficiency (ASE) and water repellency efficiency (WRE) as well as bending (MOE, MOR) and internal bonding strength (IB) were determined. Resistance against a subterranean termite, Coptotermes curvignathus Holmgren, was tested. The degradation of hemicelluloses and cellulose, that are mainly responsible for wood wetting processes, was confirmed by Fourier transform infrared (FTIR) spectra. Formation of an elevated cross-linking density in lignin also contributed to the dimensional stability, where 93.6% ASE and 46.3% WRE were achieved in the samples treated at 220°C. Mechanical properties of treated samples were inferior to the control samples due to hemicelluloses degradation and breakage of the UF bonding network. A significant improvement in termite resistance has been found in the treated samples.

Dimensional stability of heat oil-cured particleboard made with oil palm trunk and rubberwood

Dimensional stability of heat oil-cured particleboard made with admixture of oil palm trunk and rubberwood was evaluated. Particleboard made with oil palm trunk had better dimensional stability due to better compact ratio and lower hygroscopicity than rubberwood. Combination of repellent properties of oil and application of heat had greatly reduced the hygroscopicity of particleboard by decreasing its equilibrium moisture content, thickness swelling and water absorption.

Performance of compreg laminated bamboo/wood hybrid using phenolic-resin-treated strips as core layer

Physical and mechanical properties of compreg laminated bamboo/wood hybrid using phenolic-resin-treated strips as core layer were investigated. Compreg laminates made from treated core layer revealed better properties than the untreated control samples. Compreg laminated wood showed lower properties compared to compreg laminated bamboo and bamboo/wood hybrid. Assembly orientation exerted great influence on the properties as parallel laminated samples showed better strength and dimensional stability.

Mechanical properties of PP/kenaf core nanocomposites made from nanocrystalline cellulose as an additive

Kenaf core contains a fairly high amount of cellulose and lignin; hence, any attempt to use both components would be beneficial. In this study, kenaf core was used as reinforcement in PP/kenaf core nanocomposites. The core was prepared in two forms: (i) as micron-size reinforcement and (ii) as nanocrystalline cellulose. The bleaching process for nanocrystalline cellulose was conducted at different intensities in order to retain different amounts of lignin in the pulp. Then, the nanocrystalline cellulose was prepared via hydrolysis reaction. Both the micron-size kenaf core pulp and the nanocrystalline cellulose of different bleaching intensity were loaded in the polypropylene matrix with the aid of maleic anhydride grafted polypropylene coupling agent. The mixtures were then hot pressed at 180°C for 8 min to form into standard testing size sample according to standard ASTM D638 (dumbbell shape for tensile test) and D790 (for flexural and impact test). The chemical, mechanical and morphological properties of the composites were evaluated. The results revealed that composites added with unbleached nanocrystalline cellulose (11.48% lignin content) had lowered the tensile and flexural strength. On the contrary, the impact strength was increased when unbleached nanocrystalline cellulose was added.

Development and Characterization of Wood and Non-wood Particle Based Green Composites

Production of green composites involve a manufacturing process that combining both renewable plant-based particles and green polymers. Characteristics of wood and non-wood particles are one of the main factors that influencing the properties of green composite, particularly particle based composite i.e., particleboard and wood plastic composite (WPC). Characterization of wood and non-wood particles are vital for properties determination of the resulting particleboard and WPC. The present work reviewed some characterization studies of particles including the size (length, width, and thickness, aspect ratio, and slenderness ratio) and geometry of the particles. This paper also highlighted the effects of particle size and geometry of wood and non-wood particle on the mechanical and physical properties of particleboard and WPC. Findings revealed that particle size exerted significant effect on the mechanical and physical properties of both particleboard and WPC. On the other hand, types of materials (wood or non-wood) are crucial factor that affects the performance of particleboard, but not a critical factor on the performance of WPC as it contained lesser amount of particles.

Preliminary study on properties evaluation of cement added gypsum board reinforced with kenaf ( Hibiscus cannabinus ) bast fibres

Gypsum boards had poor dimensional stability and mechanical properties compared to cement boards. To improve its properties, gypsum–cement boards reinforced with kenaf fibre bast using different gypsum/cement mixing ratios was fabricated in the current study. The results revealed that addition of cement generally improved the bending strength and compressive strength of the gypsum boards. Dimensional stability attributes, water absorption and thickness swelling, were also enhanced along with increasing cement ratio. Significant improvement was observed when 70% cement was added whereas the effects of adding 30–50% on properties improvement are not significant.

Physico-mechanical properties of particleboard made from heat-treated rubberwood particles

Physico-mechanical properties of particleboard fabricated from heat-treated rubberwood particles were investigated. Reduction in water absorption and mass loss were observed in heat-treated rubberwood particles, and it was associated with the properties of particleboard. The density and moisture content of the particleboard decreased with increasing treatment temperature and time. Heat treatment of particles improved the dimensional stability of the particleboard, but the mechanical properties were adversely affected.