Toughness and microscopic fracture mechanisms of unfilled and short-glass-fibre-filled poly(cyano arylether)

• DOI: 10.1007/bf00367893
• Publication Date: 2004-11-07T04:09:31Z
• Authors: N. S. Choi; K. Takahashi
• Keywords: Tearing; Toughening; Fractography

Fracture mechanisms of an advanced high-strength thermoplastic poly(cyano arylether) (PCAE) and its short-glass-fibre (SGF)-reinforced composites have been studied in relation to toughnesses K c and J c. Test temperatures were 23 and 100 °C. Reflected and transmitted optical observations were combined with scanning electron microscopy for the fractographic investigation. For unreinforced PCAE tested at 100 °C, the damage area in front of a notch becomes fairly large in size and consists of numerous tensile microfailures around the local plastic yielding zone, as compared with that tested at 23 °C. This resulted in a substantial improvement of K c and a big increase in J c. Filling fibres, however, produced both toughening and anti-toughening results: effects of fibre spanning, pull-out and bridging across the local plastic failure zone and zigzag propagation of fracture due to fibre filling, improved the toughness. However, adhesive failure at the fibre-matrix interface, tensile microcleavage at the fibre ends and straightforward fracture in the skin layer, considerably diminished the values of K c and J c, except for the trend of K c at 23 °C.