이온가교 EVA 제조 및 열적, 기계적, 유변학적 특성과 형상기억특성 연구

Abstract

Zinc salt ionomer of maleated ethylene vinyl acetate (Zn-mEVA) were prepared by melt mixing of mEVA having a small degree of crystallinity with zinc oxide (ZnO) and stearic acid (SA). The structure, thermal, mechanical and rheological properties of the Zn-mEVA ionomer were characterized by FT-IR, DSC, DMA, tensile test and melt rheological analysis. The results revealed that the Zn-mEVA ionomers exhibits an excellent thermally-triggered shape memory effect when the temporarily fixed shape is heated above their Tm. Ionomeric polyblend of zinc salt of mEVA and poly(ethylene-co-acrylic acid) (PEA) were prepared by melt blending. Dynamic mechanical analysis of the ionomeric polyblends showed that the blends form a physically crosslinked network structure and there are sudden drops in the storage modulus at well-separated temperatures in the range of 40 – 100 oC corresponding to the Tm of each component in the blends. These structural features of the blend—presence of two different crystalline domains having well-separated Tm’s within a physically crosslinked network—enable this system to exhibit triple-shape memory behavior with two different stages of temporary shape fixing and then step-wise shape recovery.