THE EFFECT OF BORON COMPOUNDS IMPREGNATION ON PHYSICAL AND MECHANICAL PROPERTIES OF WOOD POLYMER COMPOSITES

Abstract

Wood polymer composites were prepared by styrene (ST) and different boron compounds impregnated sapwood of Oriental beech (Fagus orientalis L.) Boric acid (BA), borax (BX) and their mixture (1:1; w/w) aqueous solutions at 0.25, 1.00, and 4.70 % concentrations were prepared and then impregnated into wood prior to styrene treatment. The effects of borates pretreatments on the physical and mechanical properties of composites were evaluated. Results showed that styrene considerably improved physical properties of wood such as enhanced color, oven dry density and reduced water absorption (WA) level of wood. The polymerization of styrene and the presence of polystyrene in the wood structure were confirmed by FTIR spectroscopy. It can be seen that the WA values of wood samples with boron pre-impregnated WPCs were increased slightly when compared with only styrene treated wood samples, but still they have lower values than that of the untreated wood. It was also found that the styrene treated wood samples showed better mechanical properties such as higher modulus of rupture (MOR) and compression strength parallel to grain (CSPG). The MOR and CSPG levels of WPCs pre-impregnated with borates were decreased to some extent, but still they exhibit higher the MOR and CSPG values when compared with the untreated wood.