Chemical modification of Petersianthus macrocarpus (essia), to determine whether durability depends on bulking or hydroxyl substitution

Abstract

Wood is a biodegradable material. Decay resistance of wood is improved when the wood is chemically modified. The decay resistance of a chemically modified wood is improved as the modification stabilizes the cell wall polymers against enzyme attack due to the blocking of accessible hydroxyl groups of the cell wall polymers which reduces the amount of water for hydrolysis. The improved durability of the modified wood as a result of reducing the amount of water molecules into the cell wall for hydrolysis will depend on either bulking or percentage hydroxyl substitution (%OH). Petersianthus macrocarpus (essia), a tropical hardwood species was chemically modified with acetic anhydride (AA) and pentanoic anhydride (PA) in dry pyridine to improve its decay resistance. Graveyard test was used to analyze the effect of the modification on the decay resistance of the wood in twelve weeks in-ground contact. Percentage weight loss and visual decay grades were used to evaluate whether the decay resistance depends on weight percentage gain or percentage hydroxyl substitution. The decay resistance of the modified samples were found to be dependent on bulking.