Accelerated weathering of EPON-IPD thermosets reinforced with carbon black

This study elucidates the role of two carbon black nanofillers (V9A32 and M900) in mitigating the cyclic impact of UV and condensation on thermosetting shape memory polymer capable of high enthalpy storage of shape memory composed of EPON 826 (bisphenol A) and isophorone diamine. Samples were subjected to cyclic UV and condensation for 100, 300, 600, and 1000 h. The chemical, thermal, and morphological properties were examined. FTIR spectroscopy showed that samples prepared with V9A32 exhibited the highest chemical stability at 1000 h of exposure. Attenuated total reflectance Fourier-transform infrared microspectroscopy (µATR-FTIR) mapping was applied to visually track the surface degradation of the composites. µATR-FTIR mapping showed that carbonyl formation increases with exposure, and carbonyl preferentially forms around microcracks and inclusions. Differential scanning calorimetry results showed that the combined effect of UV and condensation leads to chain scission and plasticization, resulting in decreased glass transition temperatures. Morphological examination showed the formation of chalklike particles during the UV cycle that are washed off in the condensation cycle, resulting in weight loss with time. The results comprehensively show that carbon black improves the weathering of these epoxies.