Curing and thermal behavior of epoxy resins of hexafluoro - bisphenol –A and bisphenol-A

Abstract

This paper describes the synthesis and characterization of epoxy resins based on (hexafluoroisopropylidene)diphenol (EFN) and p,p’-isopropylidenebisphenol (EBN), respectively and 4, 4’- (hexafluoroisopropylidene)dipthalic-imideamine (IMAM), a curing agent. The synthesized epoxy resins and IMAM curing agent were characterized by Fourier Transform Infrared (FTIR) and ¹H Nuclear Magnetic Resonance (NMR) spectroscopy.¹³C NMR technique was also used to characterize IMAM. Study of curing behavior of EFN and EBN with stoichiometric amount of aromatic 4,4’-diaminodiphenylmethane (DDM), 4,4’-diaminodiphenylsulfone (DDS) and IMAM by using Differential Scanning Calorimetery (DSC) indicated that IMAM was least reactive curing agent towards both epoxy resins as compared to DDS and DDM. The investigation of thermal decomposition of the cured compounds by thermogravimetric analyzer (TGA) indicated the higher thermal stability of EFN and EBN resins initially with DDS and at elevated temperatures with IMAM. It was also observed that EFN resins were thermally more stable than EBN resins cured with corresponding curing agents.

Keywords:
aromatic diamines; curing behavior; epoxy resins; imide amine; thermal properties