Characterisation of epoxy networks resins derived from novel amine hardeners

Abstract

Tri-aryl ether and ketone amine isomers with varying meta and para aromatic substitution have been cured with a commercially available diglycidyl ether of bisphenol F epoxy resin. The mechanical and thermal properties, as well as reaction rates have been characterised and are related to specific changes in the aryl linkage groups and substitution patterns. In the case of the rate of reaction, inductive and resonance effects, from the strongly electron donating ether groups increase amine reactivity while conversely the electron withdrawing carbonyl groups reduce amine reactivity. With respect to thermal and mechanical properties, comparative molecular mobility within the rigid networks controls the mechanical and thermal properties. The carbonyl group increases Tg, char yield, modulus and strength, whilst reducing displacement at yield. Regardless of chemical linkage, increasing para substitution increased Tg and displacement at failure, whilst reducing strength and stiffness. The insights gained from this work, provide new pathways towards the rational design of a new generation of epoxy amine networks with improved processability, strength, stiffness and ductility.