Dimensional stability and durability of hybrid sandwich panel made from oil palm lumber, sengon and gmelina with boron-alum impregnation

In this study, sandwich panels made from oil palm lumber, sengon, and gmelina wood were impregnated with a boron-alum solution to improve their water and termite resistance. Water resistance testing was evaluated using a thickness swelling test following the method in SNI 03-2105. The sandwich panel was also tested for its durability against dry wood termites, according to SNI 01-7207. The weight loss, mortality, and attack degree were used as the parameters for evaluating termite durability. The results showed that the treatment with a boron-alum solution can increase the stability, water resistance, and weight loss properties up to 73%, 41%, and 100%, respectively. The best properties of the sandwich panel were obtained by the sengon-isocyanate panel with 8% boric acid-borax and 5% alum treatment which has thickness swelling of 2.37%, water absorption of 49.04%, weight loss of 0.0124%, termite mortality of 100%, and attack degree of 0.