TiO2/Epoxy 나노복합재의 발열 특성에 관한 연구

Abstract

Recently, various nanoparticles have been used for filler in polymer matrices. The particles of nano size are whether high or not cross‐link density in polymer affects the thermal and mechanical properties of one. The properties change as a result of chemical reactions between the nanoparticles and the surface of the polymer. There are two models for nanocomposites: "repulsive interaction" and "attractive interaction"between the nanoparticles and matrix. In this study, the variation in the curing mechanism was examined when nano‐size TiO2 was dispersed into an epoxy (Bisphenol A, YD-128) with different curing agents. The results of this study showed that the exothermic temperature and Tg in the case of the nanoparticles used (Jeffamine) (D‐180) at room temperature were reduced by an increase in the TiO2 contents because of the "repulsive interaction" between the nanoparticles and the matrix. The tensile strengths were increased by increasing amounts of TiO2 until 3 wt% because of a dispersion strengthening effect caused by the nanoparticles, because of the repulsive interaction. However, such tensile properties decreased at 5wt% of TiO2, because the TiO2 was agglomerated in the epoxy. In contrast, in the case of the nanoparticles that used NMA and BDMA, the exothermic temperature and Tg tended to rise with increasing amounts of TiO2 as a result of the "attractive interaction." This was because the same amounts of TiO2 were well dispersed in the epoxy. The tensile strength decreased with an increase in the TiO2 contents. In the general attractive interaction model, however, the cross‐link density was higher, and tensile strength tended to increase. Therefore, for the nanoparticles that used NMA, it was difficult to conclude that the result was caused by the "attractive model."