Mechanical properties of carbon woven reinforced epoxy matrix composites. A study on the influence of matrix modification with polysulfone

Abstract

An experimental investigation has been carried out to study the influence of thermoplastic addition on the mechanical properties of woven carbon fiber/epoxy matrix composites. As toughening agent bisphenol-A polysulfone, PSu, has been added to the epoxy matrix. Flexural tests have been performed to characterize the mechanical behavior of unmodified and PSu-modified bulk tetra- and bifunctional epoxy matrices and also for the corresponding woven carbon fiber, CF, composite materials. Three-point notched flexural tests have been used to investigate the influence of polysulfone addition in the mode-I fracture properties of the bulk epoxy matrices, relating them to their microstructural features investigated by atomic force microscopy (AFM). The double-cantilever beam (DCB) and the end-notched flexural (ENF) tests have been applied to characterize the interlaminar fracture toughness of the corresponding composites. For composites, the flexural properties were similar independent of the functionality of the epoxy matrix and of the thermoplastic content. Nevertheless, PSu addition to the epoxy matrix dearly enhanced the mode-I and II interlaminar fracture toughness of the corresponding composites, the improvement being higher for the composites manufactured with the bifunctional epoxy matrix at every thermoplastic content because of the lower crosslink density of the epoxy matrix.