163 Journal of Oil Palm Research Vol. 26 (2) June 2014 p. 163-169 ABSTRACT Rapid price increases and reduction in the supply of rubberwood has forced the particleboard manufacturers to look for new alternative raw materials. The production of particleboard from other wood species will be a good solution to the problem of depleting wood supplies. The objective of this study was to evaluate the properties of particleboard made from rubberwood and oil palm trunk pressed at diferent temperatures and times compared to particleboards made from single species. Two types of UF resins (E1 resin and SE0 resin) were applied in this study. The efect of surface-to-core ratio was also examined in this study. The modulus of rupture, internal bond strength and thickness swelling of the boards were evaluated based on the Japanese Industrial Standard for particleboard (JIS A 5908:2003). After evaluation, the panels produced are a potential substitute to the panels made from pure rubberwood. Keywords: thickness swelling, mechanical properties, physical properties, oil palm trunk, urea formaldehyde resin, rubberwood. Date received: 17 July 2013; Sent for revision: 23 October 2013; Received in inal form: 4 April 2014; Accepted: 28 April 2014. * Faculty of Forest, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia. E-mail: hua_cai81@hotmail.com ** Institute of Tropical Forestry and Forest Products, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia. MECHANICAL AND PHYSICAL PROPERTIES OF OIL PALM TRUNK CORE PARTICLEBOARD BONDED WITH DIFFERENT UF RESINS LEE, S H*; H’NG, P S*; LUM, W C*; A ZAIDON*; BAKAR, E S*; NURLIYANA, M Y*; CHAI, E W* and CHIN, K L** INTRODUCTION Rubberwood is a very important material for the Malaysian furniture industry. Traditionally, rubberwood has been the main raw material used for particleboard production as it is a favourable medium-density hardwood and is of a natural light colour (Balsiger et al., 2000). Rubberwood serves as a substitute for certain tropical hardwoods that now risk depletion. As the growth of the rubber trees is relatively rapid, and as they are comparatively inexpensive to cultivate they represent an economically sustainable resource that can be a viable alternative to the increasingly rare tropical timbers. During the 1970s and 1980s, the supply of rubber as a raw material was in abundance, and this could be attributed to the success of particleboard in the wood-based industry in Malaysia (Rahman, 2002). However, since oil palm provides a higher rate of return than rubber and requires a lower labour input, concerns related to the long-term sustainability of the entire rubber and rubberwood- based furniture industry arise from the conversion of rubber plantations to oil palm. As the supply of rubberwood for particleboard production is fast declining, the use of oil palm trunk as a source of raw material for particleboard processing becomes an interesting alternative. Oil palm trunks can be considered as a substitute for rubberwood due to the increasing land area of oil palm plantations in Malaysia. The oil palm trunk is a lignocellulosic material rich in carbohydrates in the form of starch and sugar and contains cellulose, hemicelluloses and lignin (Murai et al., 2009). It is abundant as waste material in replanting sites in Malaysia as well as in many parts of South-east Asia (Sreekala et al., 1997). Large quantities of these waste