| 초록 |
In this work, polyesters were used to improve the toughness of the diglycidylether of bisphenol A (DGEBA)/catalyst systems. The N-benzylquinoxalinium hexafluoroantimonate (BQH) was used as an cationic catalyst for thermal curing system and the content of polyester was varied with in the 0, 2.5, 5, 7.5, and 10 wt%. The cure activation energies (Ea) were determined by Flynn-Wall-Ozawa's equation with dynamic differential scanning calorimetry (DSC). The glass transition temperature (Tg) and thermal stability factors of the cured specimens were investigated by dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA), respectively. For the mechanical interfacial properties of the specimens, the critical stress intensity factor (KIC) tests were performed and their fractured surfaces were examined by using a scanning electron microscope (SEM). As a result, KIC of the modified DGEBA/BQH systems showed higher than those of neat DGEBA/BQH system and exhibited a maximum value of KIC in the 5 wt% of polyester content. This was probably due to the fact that the introduction of polyester into the net work structure of the DGEBA/BQH systems, led to an improving of the toughness of the cured DGEBA systems.
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