The efficiency of various toughening agents in novel phenolic type thermoset resin systems

Two novel phenolic type thermosetting resin systems are investigated regarding the effectiveness of different toughness modifiers. These modifiers derive from different groups such as elastomers, thermoplastics, and core–shell polymers. Measurements are accomplished by mechanical, thermal, and microscopical studies. Toughness improvement is determined by increasing KIc and GIc values while glass transition temperature, flexural strength, and modulus must not suffer greatly. Suggestions on the mechanisms of toughness modification in the novel resins are made based on images from scanning electron microscopy.