Synthesis and properties of cycloaliphatic epoxy resins containing imide and diphenyl sulfone

A novel variety of cycloaliphatic epoxy resins containing imide and diphenyl sulfone (named as 4,4′-bis[4-(4,5-epoxy-1,2,3,6-tetrahydro-phthalimido) phenoxy] diphenyl sulfone, BIES) is designed and synthesized through the three-step procedure. The mixtures of BIES and diglycidyl 4,5-epoxycyclohexane-1,2-dicarboxylate (TDE-85) are cured with methyl tetrahydrophthalic anhydride. Fourier transform infrared spectrum and proton nuclear magnetic resonance spectrum confirm that the BIES contains the chemical structure of imide and diphenyl sulfone. The measurements of glass transition temperature (Tg), heat distortion temperature (HDT), and the 5% weight loss temperature (T5%) show that the co-cured BIES/TDE-85 exhibits excellent heat resistance. For the BIES/TDE-85 with mass ratio of 0.2, Tg, HDT, and T5% of the co-cured epoxy are 175°C, 162°C, and 290°C, respectively. The impact strength increases from 117 J m−1 to 139 J m−1 with the increasing of the mass ratios of the BIES/TDE-85 from 0 to 0.2.