SYNTHESIS AND CHARACTERIZATION OF NOVEL THERMOPLASTIC ELASTOMERS BY CATIONIC LIVING POLYMERIZATION

为了开发新型热塑性弹性体(TPE)，提出了一种设计：在特级热塑性弹性体中形成微区。该设计是通过环氧乙烷和四氢呋喃等环状单体的活性阳离子聚合、疏水橡胶分子上的亲水链段接枝和聚合物共混来实现的，四氢呋喃中的活性阳离子物种与联吡啶反应生成了具有很好弹性性能的离子烯型离子弹性体。DSC、动态力学分析(DMA)测试表明，聚醚基质中形成了离子簇。小角X射线散射(SAXS)技术揭示了这种离子烯型热塑性弹性体非常独特的片层结构。在卤化丁基橡胶上接枝聚氧乙烷(PEO)或糖单元也导致了热塑性弹性体的形成。DSC、DMA和SAXS表明，这些丁基橡胶-g-亲水链段是没有任何交联性的弹性体，即它们是TPE。还研究了更简单的机械共混的TPE。在溶液浇注成膜技术中，溶剂的挥发速度可能是非常重要的。研究了溶剂挥发速率对聚氨酯的影响：通过红外二向色性测试分析了拉伸条件下聚氨酯薄膜的形态。在此基础上，对聚氨酯作为人体软组织的性能进行了评价，以期获得生物相容性较好的软组织材料。

For a development of novel thermoplastic elastomers (TPE) , a design was proposed : Formation of microdomains by an result in the TPEs of special grade. This design was realized by the syntheses using living cationic polymerizations of cyclic monomers such as ethylene oxide and tetrahydrofuran, grafting of hydrophylic segments onto hydrophobic rubber molecule, and polymer blending.Living dicationic species from tetrahydrofuran were reacted with bipyridine to result in the formation of ionene type ionic elastomers which showed very good elastomeric properties. DSC,dynamic mechanical analysis (DMA) measurements suggested ion cluster formation in the polyether matrix. Small-angle X-ray scattering (SAXS) technique revealed very unique lamellae structure of this ionene-type TPE.Grafting of poly (ethylene oxide)(PEO) or sugar unit on halogenated butyl rubber also resulted in TPE.Microdomain formations of hydrophilic PEO or sugar units were suggested by DSC,DMA,and SAXS.These butyl rubber-g-hydrophilic segments were elastomeric without any crosslinkings, i.e., they are TPE.TPE by more simple mechanical blending was also studied.Influence of processing conditions on the properties of TPE is assumed to be significant. In the film forming by solution casting technique, evaporation rate of the solvent may be very important. Effect of the solvent evaporation rate were studied on polyurethanes : The morphology of polyurethane films was analyzed by infrared dichroism measurement under streching of the films. In relation with this study, properties of polyurethanes as soft tissues of human body were evaluated to obtain biocompatible soft materials.