Abstract
Polymer composites from polypropylene (PP) and treated and untreated hemp fibers (HF) were prepared using a twin screw extruder and separated feeding ports. Both treated and untreated HF show reinforcing effect in PP composites but the treatments applied to HF accentuate this effect. An increase with 78 % of tensile strength and with 61 % of Young’s modulus was obtained with untreated fibers and double tensile strength and modulus when using treated HF. Aminosilane treatment of HF was the most efficient, leading to simultaneous improvement of tensile properties and impact strength of PP composites. Keywords: hemp fibers, mechanical properties, twin screw extruder, polymer composites