Effects of weathering aging on mechanical and thermal properties of injection molded glass fiber reinforced polypropylene composites

The effect of weathering aging on the degradation behavior of injection molded short glass fiber reinforced polypropylene composites (GFPP) is studied. First, the effect of outdoor weathering on mechanical properties of GFPP composite was investigated by tensile, flexural, and impact tests. Furthermore, to clarify the degradation behavior under natural weathering environments, differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) measurements were carried out to analyze the structural and molecular changes during weathering aging. The results show that weathering aging has a significant influence on changes in mechanical properties, melting temperature and the degree of crystallinity of PG6N1 without added carbon black and UV absorbing agent. Those degradations not only occurred on the surface of GFPP but also proceeded to the inner matrix and interface. However, GFPP GWH42 with added carbon black and UV absorbing agent shows excellent weathering stability.