Song Shijie, Feng Jiachun, Wu Peiyi
Key Laboratory of Molecular Engineering of Polymers of Ministry of Education, Department of Macromolecular Science and Laboratory of Advanced Materials, Fudan University, 220 Handan Road, Shanghai 200433, P.R. China.
Macromol Rapid Commun. 2011 Oct 4;32(19):1569-75. doi: 10.1002/marc.201100298. Epub 2011 Jul 26.
A new strategy that utilizes the microphase separation of block copolymer and phase transition of small molecules for preparing polymer-based shape memory elastomer has been proposed. According to this strategy, a novel kind of shape memory elastomer comprising styrene-b-(ethylene-co-butylene)-b-styrene (SEBS) and paraffin has been prepared. Because paraffins are midblock-selective molecules for SEBS, they will preferentially enter and swell EB blocks supporting paraffins as an excellent switch phase for shape memory effect. Microstructures of SEBS/paraffin composites have been characterized by transmission electron microscopy, polarized light microscopy, and differential scanning calorimetry. The composites demonstrate various phase morphologies with regard to different paraffin loading. It has been found that under low paraffin loading, all the paraffins precisely embed in and swell EB-rich domains. While under higher loading, part of the paraffins become free and a larger-scaled phase separation has been observed. However, within wide paraffin loadings, all composites show good shape fixing, shape recovery performances, and improved tensile properties. Compared to the reported methods for shape memory elastomers preparation, this method not only simplifies the fabrication procedure from raw materials to processing but also offers a controllable approach for the optimization of shape memory properties as well as balancing the rigidity and softness of the material.
提出了一种利用嵌段共聚物的微相分离和小分子的相变来制备聚合物基形状记忆弹性体的新策略。根据该策略，制备了一种新型的形状记忆弹性体，其由苯乙烯 - b -（乙烯 - 共 - 丁烯）- b - 苯乙烯（SEBS）和石蜡组成。由于石蜡是SEBS的中间嵌段选择性分子，它们将优先进入并溶胀EB嵌段，使石蜡成为形状记忆效应的优良开关相。通过透射电子显微镜、偏光显微镜和差示扫描量热法对SEBS/石蜡复合材料的微观结构进行了表征。复合材料在不同石蜡负载量下呈现出各种相形态。研究发现，在低石蜡负载量下，所有石蜡精确地嵌入并溶胀富含EB的区域。而在较高负载量下，部分石蜡变得自由，并观察到更大尺度的相分离。然而，在较宽的石蜡负载范围内，所有复合材料均表现出良好的形状固定、形状恢复性能以及改善的拉伸性能。与已报道的形状记忆弹性体制备方法相比，该方法不仅简化了从原材料到加工的制造过程，还为形状记忆性能的优化以及材料刚性和柔软性的平衡提供了一种可控方法。
