Synthesis and characterisation of new sulphur-containing epoxy networks

The position of sulphur within a cured epoxy amine network and its impact upon the thermal, mechanical, chemical and physical properties has been investigated in this study. Sulphur-containing epoxy resins, diglycidyl thioether of bisphenol A (DGTEBA) and diglycidyl ether of dithio diphenyl (DGTED) have been synthesised, cured and characterised and then compared with the benchmark epoxy resin, diglycidyl ether of bisphenol A (DGEBA). DGTEBA has two sulphur atoms located terminally to the epoxide groups, whilst DGTED has a sulphur atom located centrally between two phenyl groups. Evaluation of the properties and cure mechanism using 4,4′-diamino diphenyl sulphone (4,4′-DDS) as the hardener showed that when the sulphur was terminally located, the glass transition temperature, cure conversion, thermal stability, yield strain and stress decrease substantially, whilst the rate of cure and methyl ethyl ketone (MEK) ingress was comparatively higher. Near-infrared spectroscopy revealed that a competing hydrogen a...