This study outlines the effect of catalyst and microwave heating on the degree of acetylation in radiata pine. Samples of radiata pine sapwood were impregnated with potassium acetate (KAc) dissolved in two different solvents (water and methanol). Impregnated samples were dried and subjected to acetic anhydride loading followed by conventional and microwave heating. The degree of acetylation was evaluated by weight percent gain (WPG). Effect of reaction temperature, reaction time on rate of reaction and WPG was investigated. In the initial 30 minutes, the rate of reaction with catalyst was nearly 6 times faster than that of non-catalysed acetylation. A reaction time of 30 minute gave rise to a 25% WPG in a catalysed system while without catalyst, a maximum 23% WPG was obtained after 8 hours of curing. No significant difference in the WPG and rate of reaction was found when water and methanol were used as solvents for KAc. KAc was found to have no adverse effect upon dimensional stability whereas the percentage water uptake was significantly reduced under catalytic acetylation. Microwaves are a potential source of heating and under catalytic conditions a 20 % WPG was obtained after only 5 minutes of curing.

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