Fracture Behaviour of Chopped Glass Strand Reinforced Phenolic Composites

Abstract

Modified phenolic composites were fabricated by compression moulding a mixture of chopped glass strands and a cashew nut shell liquid modified phenolic resin. Single edge notched bend (SENB) tests, double edge notched (DEN) tension tests and 3-point flexure tests on unnotched specimens were conducted at various fibre volume fractions and strand lengths. The candidate stress intensity factors of SENB specimens were significantly higher than those of DEN specimens. Glass strand/phenolic interface debonding and strand pull-out were observed for both SENB and DEN specimens. In addition, the DEN specimens exhibited a considerable degree of splitting of glass strands parallel to their axes. By increasing the fibre volume fraction and the strand length, it was possible to improve the flexural strength without adversely affecting the fracture toughness.