Use of rubber modification technique to improve fracture-resistance of hoop wound composites

Toughness improvement of an epoxy resin and respective hoop wound composite were investigated systematically using amine-terminated butadiene acrylonitrile (ATBN) liquid rubber. Rubber modification improves fracture toughness of epoxy resin with slight reduction in the glass transition temperature (Tg), flexural and compressive properties of resin. Impact resistance of composite is improved by rubber modification similar to modified resin. Interlaminar shear strength (ILSS), compressive modulus and strength, and flexural strength of composite decreased slightly with rubber modification. To interpret the data, the void content of composite samples was determined and the damaged surfaces of fractured samples were investigated. The findings explained the performance of rubber modified specimens in comparison with the unmodified one. In addition, a simple formulation was developed to predict the impact strength of modified composite samples.