Impact fatigue of short glass fiber reinforced polycarbonate

The present study analyzes the impact properties of polycarbonate reinforced with 0, 20 and 30 wt% short glass fiber. The specimens were prepared under various injection molding conditions, such as filling time, melting temperature and mold temperature. Impact tests were performed with a Dynatup drop weight impact tester at different impact energies (1.2, 0.16, 0.12 and 0.095 J). The fracture mechanism was examined with a scanning electron microscopy. The results indicated that the specimen reinforced with 30 wt% short glass fiber showed the highest impact energy absorbed, together with the highest impact load in single impact. The absorbed energy of 30 wt% reinforced is approximately 15% higher than that of 20 wt% reinforced and about 10 times higher than that of unreinforced polycarbonate. The polycarbonate with 30 wt% short glass fiber reinforced has the highest impact number and accumulation energy in repeated impacts. The accumulation energy is approximately 15% higher than that of 20 wt% reinforced polycarbonate. The thicker the skin layer, the stronger the interfacial adhesion. The ranking of impact number and accumulation energy is in goad agreement with the distributions of the skin layer thickness in repeated impacts. The splits and tearing mechanisms dominate the single impact fracture in unreinforced polycarbonate, while the fiber pull-out and fiber breakage are the major fracture mechanisms in repeated impacts for polycarbonate composites.