초록 |
Recently, multiple-shape memory polymers that can provide more than one temporary shape in addition to their permanent original shape have attracted great interest. Specifically, triple-shape memory polymers (T-SMPs) have two temporary shapes with their permanent original shape. T-SMPs may have potential applications in smart medical devices, textiles and assembly systems. In this study, T-SMPs were prepared by melt blending of ethylene vinyl acetate (EVA) with ethylene methyl acrylate copolymer (EMA) in the presence of dibutyltin oxide as a catalyst. Rheometric analysis, DMA and DSC results revealed that the blends form a crosslinked network via the transesterification reaction between the ester bonds of component polymers in the molten state, and there appeared two crystalline melting transition at distinctly well separated regions. These structural features of the blend enable to exhibit triple-shape memory behavior with two different stages of temporary shape fixing and recovery. |