Effect of ester linkages on the mechanical properties of wood fiber-polypropylene composites

The esterification reaction between several wood fibers and maleated polypropylenes, and its role in determining the mechanical properties of wood fiber-polypropylene composites was investigated. The modification technique used in this study involved bulk treatment in a thermokinetic mixer. The treatment of wood fiber with maleated polypropylene had a significant effect in increasing the mechanical properties of the composites. However, no direct evidence of ester links was detected between wood fiber and maleated polypropylene by FT-IR. Thus, the effectiveness of maleated polypropylene in improving the mechanical properties was attributed to the compatibilization effect which is accomplished by improving the wettability of wood fiber by the matrix polymer, lowering the fiber to fiber interactions, improving fibers dispersion and orientation, and enhancing the adhesion between wood fiber and polypropylene matrix.