Analysis of axial crushing behaviour of unsaturated polyester and vinyl ester composites manufactured by out of die ultraviolet cured pultrusion

Abstract

This paper analyses the axial crushing behaviour and flexural properties of novel unsaturated polyester (UP) and vinyl ester (VE) composites, manufactured by out of die ultraviolet (UV) cured pultrusion. The relation between axial crushing properties and microstructure have been analysed based on UV curing kinetics and physical characterisation. The results show that VE composites present higher specific energy absorption capability (SEA) than UP composites, about 18% higher, due to the higher fracture toughness of VE resin. However, the slow curing kinetics of VE resin implies an expansion of the profile at the exit of the die, and consequently a high presence of voids (7.4%). In contrast, UP resin presents faster curing kinetics and therefore, the presence of voids is lower (0.9%). This fact implies a reduction in flexural strength of VE composites, which is 17% lower than UP composites.