On the curing and degradation of bisphenol A diglycidyl ether and epoxidized soybean oil compounds cured with itaconic and succinic acids

Abstract

AbstractThis work investigated the curing and degradation behavior of compounds made with 1:1 of bisphenol A diglycidyl ether and epoxidized soybean oil, cured with itaconic acid (ITA) and succinic acid (SUC), coded as EP/ITA and EP/SUC. Complex peaks observed in differential scanning calorimetry are mostly due to the catalyzed curing and homopolymerization. Fourier transform infrared spectroscopy spectra suggest that the curing follows the SN2reaction mechanism for both compounds. Lower activation energies of curing were verified for EP/ITA compared to the EP/SUC, mainly due to their greater reactivity with the epoxy matrix at temperatures below the acids structures and melting points. Regarding thermal degradation, four steps were verified: acid degradation, degradation of the non‐cross‐linked material, degradation of cross‐linked material, and carbon decomposition. EP/SUC with a molar ratio equal to 0.4 presented the lowest activation energy for degradation. The degradation's solid‐state mechanisms analysis indicated that in EP/ITA and EP/SUC compounds the processes are controlled by nucleation and subsequent growth.