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机构地区:[1]沈阳化工大学,材料科学与工程学院,辽宁沈阳110142
出 处:《高分子通报》2015年第12期71-79,共9页Polymer Bulletin
摘 要:首先通过红外光谱(IR)、核磁共振(1 H-NMR)和凝胶渗透色谱(GPC)对所选用的杜仲胶(EUG)和合成反式-1,4-聚异戊二烯(TPI)进行了微观结构分析,进而采用差示扫描量热法(DSC)和偏光显微镜(POM)对EUG和TPI的等温结晶行为进行了对比研究,重点讨论了二者链化学组成和微观结构的不同对二者等温结晶行为的影响。Avrami方程分析DSC数据结果及POM观察结果显示,EUG和TPI的成核方式和生长机理各不相同。EUG主要为均相成核,而TPI则为异相成核。EUG的等温结晶行为对温度有着更高的敏感性。EUG的结晶活化能(147.2kJ/mol)大于TPI的(114.8kJ/mol)。在37℃下熔体等温结晶,EUG所得主要为β球晶,而TPI为α和β两种球晶并存,且TPI中引发剂残渣等灰分的异相成核作用导致很早就发生了球晶间的相互碰撞。The isothermal crystallization behaviors of natural eucommia ulmoides gum and synthetic trans-1, 4- polyisoprene were comparatively studied by means of DSC and POM. The results of DSC and POM indicated that EUG and TPI exhibited different nucleation and growth mechanism. EUG was mainly homogeneous nucleation, while TPI was heterogeneous nucleation. Isothermal crystallization behavior of EUG was more sensitive to temperature. When isothermally crystallized at a low temperature (28℃), the crystallization rate of EUG was significantly higher than that of TPI; while when isothermally crystallized at relative higher temperatures(31℃-43℃), the crystallization rate of EUG was less than that of TPI obviously. The crystallization activation energy of EUG (147.2kJ/mol) was higher than that of TPI (114. 8kJ/mol). EUG formed mainly β spherulites and TPI was the a and β spherulites coexist when isothermal crystallization from melt at 37℃. In addition, the collision between spherulites appeared early for TPI due to the heterogeneous nucleation.
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