ABSTRACT

No abstract

In this study the tropical light hardwood species jelutong (Dyera costulata), terbulan(Endospermum diadenum), batai (Paraserianthes moluccana), rubberwood (Hevea brasiliensis), and pulai (Alstonia pneumatophora) were treated with benzene diazonium salt to improve their dynamic Young’s modulus (Ed), and thermal stability. Benzine diazonium salt reacted with cellulose in wood and produced 2,6-diazocellulose by a coupling reaction, as confirmed by Fourier transform infrared (FTIR) spectroscopy. Values of Ed were calculated from the free-free flexural vibration method and found to increase on treatment. The morphological properties were studied by FTIR and scanning electron microscopy (SEM) and found to be changed. Thermal properties of treated wood samples were evaluated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The treated wood samples exhibited an increased thermal stability relative to the untreated wood samples; this increase may be related to the formation of 2, 6-diazo cellulose compound.

Chemical modification is an often-followed route to improve physical and mechanical properties of solid wood materials. In this study five kinds of tropical light hardwoods species, namely jelutong (Dyera costulata), terbulan(Endospermum diadenum), batai (Paraserianthes moluccana), rubberwood (Hevea brasiliensis), and pulai (Alstonia pneumatophora), were chemically modified with benzene diazonium salt to improve their dimensional stability and water repellent efficiency. The dimensional stability of treated samples in terms of volumetric swelling coefficient (S) and anti-swelling-efficiency (ASE) were found to improve with treatment. The water repellent efficiency (WRE) values also seemed to improve considerably with treatment of wood samples. Furthermore, treated wood samples had lower water and moisture absorption compared to that of untreated ones.

This study investigates the effects of Polyvinyl Alcohol (PVA) as a binder on the mechanical and physical properties of wood polymer composites (WPCs). The WPCs were manufactured from tropical sawdust and polypropylene using a hot press molding method at five levels of sawdust loading (10–30 wt). For the manufacturing of the composites, the sawdust was chemically treated with 2‐ethylhexyl methacrylate before 10 wt % PVA was added. The flexural strength, flexural modulus, Young's Modulus, and Rockwell hardness were found to improve with the treatments. However, the binder treated wood polymer composite (BTWPC) samples exhibited better mechanical properties than the raw wood polymer composite and the treated wood polymer composite (TWPC) samples. Moreover, water absorption decreased significantly for the TWPC and the BTWPC samples, indicating that their water resistance is higher than that of the raw samples. The SEM micrographs revealed that the interfacial bonding of the BTWPC had significantly improved, suggesting that the chemical treatment led to better dispersion of the filler into the matrix, and this improved further after the addition of the binder. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013