| 초록 |
In this work, the effects of different contents of polyamideimide (PAI) on thermal and mechanical properties of epoxy/polyamideimide blend system were studied. Epoxy resins used were diglycidylether of bisphenol A (DGEBA) and 4,4-diaminodiphenyl methane (DDM) was used as a curing agent for the DGEBA/PAI system. The compositions of DGEBA/PAI blend system were varied within 100/0∼100/20 phr. Cure activation energy (Ea) obtained from dynamic DSC data by Kissinger method, increased with increasing the PAI content up to 15∼20 phr. The glass transition temperature (Tg) based on dynamic mechanical analysis (DMA) results, decreased with increasing the PAI content. The reason for the lower Tg value of the DGEBA/PAI blend can be due to a decrease in the cross-link density of epoxy, resulted from the presence of polyamideimide segments adjacent to epoxy reactive groups. For the mechanical interfacial properties of the casting specimens, the critical stress intensity factor (KIC) test was performed. The KIC values of the blend system increased with increasing the PAI content up to 15 phr, but remained constant after higher PAI content. This resulted from the immiscibility of the blend system, occurred in excessive addition of PAI content to epoxy resins.
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