Effect of poly ethylene co vinyl acetate grade on water resistance and mechanical properties of particleboard
Three layer particleboard was prepared in the laboratory using a similar composition and processing condition to those used in the plant production of particleboard. Poly(ethylene co vinyl acetate) (EVA) was mixed with natural rubber wood particles in the core layer to reduce the water resistance of the particleboard. The properties of three EVA grades with vinyl acetate contents of 19% 22% and 28% were melt indexes of 530, 1.8, and 6.8 g/10 min, melting temperatures of 84, 86, and 75 C, and molecular weights of 29000, 68000, and 61000 g/mol, respectively. The addition of 5% EVA significantly decreased the thickness swelling and water absorption properties of the particleboard. The mechanical properties of the particleboard that were determined were the modulus of rupture, modulus of elasticity, internal bond strength, and screw holding force. A statistical analysis of the data showed that the addition of 5% EVA did not deteriorate the mechanical properties. EVA22 seemed to be the optimal grade.