Wool fibers as low cost reinforcement in polypropylene matrix

In the present work polypropylene (PP)-based composites containing wool fibers, grinded, washed and desiccated, were prepared by melt blending in an internal batch mixer. The effect of wool fibers content on the composite mechanical properties was determined. Wool fibers have a hydrophilic character due to the presence of about 70% of hydrophilic amino acids in the amino acidic sequence of keratin. For this reason, in order to increase their compatibility with a hydrophobic matrix, small amounts of PP grafted with maleic anhydride (PP-g-MA) were added to the composites. Adhesion, thermal and mechanical properties of the composites were evaluated as a function of both the grafting degree of the compabilizer and the fiber length.