PP LDPE BLENDS FILLED WITH SHORT POLYAMIDE FIBERS/

The effect of short polyamide 66 (PA) fibers on the tensile, flexural, and impact behaviour of low density polyethylene (LDPE), polypropylen e (PP), and their blends has been investigated. The moduli of the comp osites increase as fiber and PP contents increase, and this effect is more noticeable at LDPE/PP ratios above 1. However, the effect of the fibers on the tensile and flexural strength of these materials depends on matrix composition. So, the polyamide fibers act as a reinforcing agent for polymer matrices with LDPE/PP ratios above 1, but with PP as the continuous phase a decrease in the tensile strength is observed. In all cases, at the same fiber content, the strength of the composite s increases as PP percentage increases. On the other hand, the additio n of PA fibers gives rise to an increase of the tenacity of the compos ites with PP percentages above 50% in the matrix composition. From the observed results a higher reinforcing effect and a better affinity be tween the polyamide fibers and the LDPE are suggested.