Preparation of polymer composites from polypropylene and sawdust

Abstract

In this work, polypropylene (PP) /sawdust composites containing 10-50% by weight of sawdust and surface-modified sawdust were prepared by two roll mill followed by compression molding and the effect of sawdust content and surface-modifying agents on mechanical properties of the PP/sawdust composites were studied. It was found that sawdust in PP increased the stiffness and hardness while the tensile strength, elongation at break and impact strength decreased. However, the surface morphology of this type of composite revealed incompatibility and poor interfacial adhesion between the sawdust and PP. Thus, the esterification reaction using butyryl chloride, dodecanoyl chloride and stearoyl chloride were adopted to modify surface of the sawdust prior to mix with the PP matrix. The optimum of amount of ester was 50% which led to the highest mechanical properties. Experimental results revealed that the mechanical properties of the composite with butyrated sawdust was better than the ones with unesterified sawdust. Likewise, the dodecanoyl chloride and stearoyl chloride helped promoting the compatibility between the sawdust and PP. Although, comparing to the composite with butyrated sawdust, the strength of the composites with dodecanoated sawdust and stearoated sawdust were lowered, this surface treatment increased the elongation at break and impact strength of the composites