Improving interfacial adhesion in pla/wood biocomposites

摘要

Two reactive coupling agents, N,N-(1,3-phenylene dimaleiimide) (BMI) and 1,1-(methylenedi-4,1-phenylene)bismaleimide (DBMI) were used to improve interfacial adhesion in PLA/wood composites. First the effect of the coupling agents was established in a series of experiments in which the amount of coupling agent changed at constant wood content, and then the effect of coupling was determined at various wood loadings (0-60 vol%). Composites were homogenized in an internal mixer and compression molded to plates. Tensile properties were determined and micromechanical deformations were studied by acoustic emission measurements. The two compounds improved the properties of the composites. Stiffness, strength and deformability increased simultaneously supplying sufficient proof for coupling. Because of the flexibility of the molecule, DBMI is a more efficient coupling agent in the studied composites than BMI. However, the effect of coupling is small, because only a few very large particles debond under the effect of external load. Smaller particles adhere strongly to the matrix even without coupling proving that interfacial adhesion is strong in PLA/wood composites.