Synthesis of tri-aryl ether epoxy resin isomers and their cure with diamino diphenyl sulphone

The synthesis of bi‐ and tetra‐functional tri‐aryl ether epoxy resin isomers and their subsequent cure with 44 diamino diphenyl sulphone (DDS) is presented here. The effect of varying aromatic substitution and cross‐link density on the structure, property, and processing relationships is explored for 1,3 bis(3‐glycidyloxyphenoxy)benzene (133 BGOPB), 1,4 bis(4‐glycidyloxyphenoxy)benzene (144 BGOPB), N,N,N,N‐tetraglycidyl 1,3‐bis (3‐aminophenoxy) benzene (133 TGAPB), and N,N,N,N‐tetraglycidyl 1,4‐bis (4‐aminophenoxy) benzene (144 TGAPB). Meta substitution to the aromatic ring reduces the rate of reaction, glass transition temperature, yield strain and crosslink density, coefficient of thermal expansion, and side reactions, while increasing strain softening, compressive modulus and strength, and methyl ethyl ketone ingress. Increasing crosslink density increases the glass transition temperature, promotes side reactions during cure, and increases compressive modulus, strength, and yield strain, while reducing coefficients of thermal expansion, methyl ethyl ketone ingress, and density. The results are discussed in terms of packing efficiency of the meta‐substituted epoxy resins and the role of short range molecular mobility caused by the lack of an aromatic axis of rotation.