Impact fatigue behaviour of rubber-modified glass fibre reinforced polyamide 6

The impact fatigue behaviour of glass fibre reinforced polyamide 6 with and without impact modifier was studied. The accumulated damage was investigated by means of light microscopy, confocal laser scanning microscopy and scanning electron microscopy. The impact modifiers were found to increase the ductility of the matrix. In particular, the increase resistance to crack initiation and growth during biaxial impact fatigue was demonstrated. The rubber particles cavitate during impact testing and initiate local shearing, thereby reducing the amount of debonding at the fibre ends, as compared to the sample without toughness modifiers. The shearing of the matrix suppresses debonding, matrix flaws at the fibre ends and fibre pull-out. SEM micrograph of the fracture surface of a sample tested in single blow impact. [GRAPHICS]