Enhancement of flexural properties and dimensional stability of rice husk particleboard using wood strands in face layers

Major drawbacks of rice husk particleboards are low flexural modulus and strength, and dimensional stability compared with strandboards made from wood strands. This study investigated the flexural properties and dimensional stability of the sandwich-structured composites comprising the rice husk particles in the core layer and randomly aligned the wood strands in the face layers. The design of three layer structure comprising a core layer of rice husk sandwiched between two ash wood strand layers were 5:90:5, 10:80:10, 15:70:15, 20:60:20 face:core:face ratios (by weight). The presence of the face strands significantly improved the flexural modulus and strength, and the dimensional stability. As compared with the rice husk particleboards, incorporation of 10-40% of the strands in the face layer of the specimens improved the flexural modulus and strength by 21-166% and 35-202%, respectively. The effect was most pronounced beginning with 30 wt.% the wood strands. The sandwich-structured composites with the wood strands in the face layer (40 wt.% of the panel weight) and the rice husk particles in the core layer (60 wt.% of the panel weight) can be evaluated as a substitute for the strandboards in structural applications. (C) 2012 Elsevier Ltd. All rights reserved.