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Polyethylene terephthalate(PET)/polycaprolactone(PCL) segmented copolymers with different hard segment contents and a blend of two of them were studied by using DSC, WAXS, TEM and IR techniques and dynamic mechanical, stress-strain and isothermal crystallization measurements. Emphasis was laid on the studies of influence of compositional heterogeneity on the morphology and properties of these segmented copolymers. It was found that the solution cast specimens of the more heterogeneous sample exhibit better segregation of segments, high crystallinity and melting temperature. They have higher thermal stability of mechanical properties at small deformations. However, they are less stable against large deformations and may become softer than the more homogeneous ones. 相似文献
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<正> 通常人们采用X-射线法和红外二向色性法等获得有关高聚物材料的晶区取向和分子链上某些特定基团的取向状况,但存在着设备要求高且操作复杂的弊端。Schael和Samuels等发展了利用改装型阿贝折射仪,可以方便地同时获得高聚物薄膜样品(聚烯烃和羟基丙基纤维素等)三个轴向上的折射率。有关聚酯(PET)的报道则不多见。本工作主要研究了不同拉伸条件(拉伸方式和拉伸速率等)对PET薄膜取向状况(折射率和 相似文献
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Spherulites of different morphological features have been obtained by varying the cooling rateof polypropylene melts through the crystallization temperature range from 120℃to 90℃. It wasfound that SALS is very sensitive to the changes of internal structure of the spherulites, and information about their morphological difference can be obtained according to the model theories and statisticaltheories of SALS. 相似文献
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小角光散射(SALS)是利用由于物体内极化率的不均一性引起的散射来研究结构的一种方法,散射测量的角度通常在10°以内.1959年Plaza和Stein[1]第一次用SALS方法研究了聚乙烯薄膜并得到了反映球晶结构的典型散射图象.自此以来,由于激光技术的发展和小型激光器普遍使用,使得SALS的实验工作大为方便.理论研究的进展又使从散射图象能得到的信息日益丰富.SALS方法和各种显微镜技?... 相似文献
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一、引言同步辐射(Synchrotron Radiation)是高能物理研究的产物。同步辐射光源的出现,是近代科学发展史上的重大事件。十余年来,应用同步辐射光源业已取得大量的科技成果,而且越来越显示其巨大的生命力。它可与本世纪三十年代带电粒子加速器的出现而将核物理推向新的巅峰相媲美。由于同步辐射光源具有综合的优异特性,如今已成为多种学科的强有力的研 相似文献