Effects of weathering on mechanical properties and surface roughness of Endospermum malaccense wood modified with propionic anhydride

This study evaluated some properties of sesenduk (Endospermum malaccense) wood treated with propionic anhydride and exposed to outdoor conditions for up to one year. Defect-free samples of sesenduk were extracted with a 3:1:1 (v/v) mixture of toluene, ethanol and acetone for 3 hours at a temperature of 100°C. The samples were then modified at the same temperature for another 3 hours using propionic anhydride and 10% sodium formate as catalyst. Modulus of elasticity (MOE), modulus of rupture (MOR) and parallel-to-grain compression strength of the samples exposed to weathering were tested. Chemical treatment reduced the MOE but slightly increased the MOR and parallel-to-grain compression strength compared with untreated samples. However, treated samples retained higher strength properties than untreated ones. The modulus of elasticity, modulus of rupture and parallel-to-grain compression strength of treated samples at radial orientation were respectively 20%, 31% and 62% higher than those of untreated samples after one year’s outdoor exposure. Weathering adversely influenced the surface quality of the specimens for all exposure times.