Degradation Study of Polypropylene Based Composites Containing Weld Lines

This work deals with the natural weathering of PP composites containing weld lines. Single and double-gated injection molded bars were exposed to natural environment in Campina Grande (Brazil) for periods up to 45 weeks and they were tested for mechanical properties, surface fractography and IR spectroscopy.

The results pointed that weld lines make the parts weaker, although the strength loss caused by weathering of double injected samples was similar to the ones produced by single-gated injection. It was also observed peculiar characteristics such as strength recovery after long term weathering and adhesion reduction of the glass fiber composites.