Comparison of Fracture Energies of Epoxy-polysulfone Matrices and Unidirectional Composites Based on Them

Abstract

The fracture energies of modified epoxy matrices and unidirectional glass (GFRP)-, organic (OFRP)-, and carbon (CFRP)-fiber-reinforced plastics based on them are compared. The unidirectional composites were fabricated by winding. Epoxy-polysulfone compositions were used as matrices containing from 5 to 20 wt.% of PSK-1 polysulfone. The matrices were cured with triethanolaminotitanate. It is shown that the fracture mechanisms of GFRP, OFRP, and CFRP in shear differ, which is supposedly related to the nature of fibers. The fracture energy of reinforced plastics is mainly determined by the impact strength of matrix. The delamination energy G IR cm of GFRP, OFRP, and CFRP increased monotonically with content of polysulfone in the matrix. A marked growth in G IR cm was observed at a content of polysulfone exceeding 10 wt.%. The crack resistance of the composites under investigation increased two times. The fracture toughness of GFRP and OFRP was 3-4 times higher than that of CFRP at any concentration of polysulfone. A growth in G IR m of the matrices started when the content of PSK-1 exceeded 5 wt.%, and at 15-20 wt.% of PSK-1, the values of G IR m increased four times. In all the cases investigated, a correlation between the crack resistance of reinforced plastics and that of polymeric matrices was observed.