Three-layer particleboards of Type 1 showed significant average increment of modulus
of elasticity that was 56% and 79% higher than those of the 100% kenaf stem and 100% kenaf core
particleboards, respectively. Adding kenaf stem to the middle layer up to 30% of its composition gave
the highest values of modulus of rupture, modulus of elasticity, and internal bonding and the lowest values
of thickness swelling and water absorption. All three-layer panels with kenaf stem in the middle layer
met the requirements of the Japanese Industrial Standard JIS A 5908, especially for modulus of rupture,
modulus of elasticity, and internal bonding.