Synthesis, characterization and thermal oxidative stability of rigid epoxy polymers cured from aromatic mono- and di-amines

Abstract

Synthesis, characterization and thermal properties of some rigid epoxy polymers cured from aromatic mono- and di-amine are presented. The aromatic mono- and di- amine are prepared via nucleophilic substitution reaction of p-nitrochlorobenzene with the respective mono- and di- hydroxybiphenyl, and via subsequent hydrogenation of the aromatic nitro products. The structures of both, mono- and di-amines, are confirmed by Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance ( 1 HNMR) and elemental (CHN) analysis. Furthermore, three types of rigid epoxy polymers, (i) HBREP, (ii) HCREP, and (iii) BCREP, are prepared by melt processing and curing of the epoxy monomers with (i) monoamine, (ii) diamine, and (iii) 1: 1 mixture of mono- and di-amines, respectively. These rigid epoxy polymers are characterized by FTIR spectros- copy, X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). TGA and DSC results show excellent thermal oxi- dative stability (Td10≥400 °C) and substantially high glass transition temperatures (Tg080-120 °C) for these rigid ep- oxy polymers. The intermediary BCREP exhibits the high- est Tg as well as the maximum heat resistance and thermal stability regardless of its lower chemical crosslink density with respect to HCREP. The kinetic analyses of the oxida- tive degradation of polymers also reveal sufficiently high activation energy of pyrolysis for BCREP.