Temperature-dependent β-Crystal Growth in Isotactic Polypropylene with β-Nucleating Agent after Shea

来源 :Chinese Journal of Polymer Science | 被引量 : 0次 | 上传用户:a15813225802
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
In our current work, the effect of the shear temperature on the growth of β-crystal in isotactic polypropylene(iPP) with β-nucleating agent is investigated by means of in situ two-dimensional wide-angle X-ray diffraction(2 D-WAXD). At low shear temperatures, the formed shear-induced oriented precursors are hard to relax back to random coiled state due to the weak mobility of molecular chains. Therefore, plenty of oriented α-crystals are induced by shear-induced oriented precursors, while β-crystal is greatly depressed. As the shear temperature increases, oriented β-crystal gradually increases along with the decrease of α-crystal. It is deduced that the shear temperature at which the content of β-crystal increases to the(maximum) value found in quiescent crystallization is almost the same as that at which the accelerating effect of flow on crystallization kinetics is completely erased. Our work manifests its significance in regulating β-crystal and thus in the structure and property manipulation of i PP. In our current work, the effect of the shear temperature on the growth of β-crystal in isotactic polypropylene (iPP) with β-nucleating agent is investigated by means of in situ two-dimensional wide-angle X-ray diffraction (2 D- WAXD). At low shear temperatures, the formed shear-induced oriented precursors are hard to relax back to random coiled state due to weak charges of molecular chains. Thus, plenty of oriented α-crystals are induced by shear-induced oriented precursors, As the shear temperature increases, oriented β-crystal is increases with the decrease of α-crystal. It is deduced that the shear temperature at which the content of β-crystal increases to the (maximum) value found in quiescent crystallization is almost the same as that that which the accelerating effect of flow on crystallization kinetics is completely erased. Our work manifests its significance in regulating β-crystal and thus in the structure and prop erty manipulation of i PP.
其他文献
请下载后查看,本文暂不支持在线获取查看简介。 Please download to view, this article does not support online access to view profile.
光化学诱导动态核极化(photo-CIDNP)是一种在光照条件下由于产生非玻尔兹曼核自旋极化而使核磁共振(NMR)波谱信号强度发生明显变化的效应。这种效应在液体NMR中已为人所熟知,
颐和园、香山、圆明园将组建皇家园林旅游区,打造成世界一流的特色旅游区和世界一流的文化消费区。据海淀区旅游局有关人士介绍,规划中的皇家园林旅游区涵盖了香山、青龙桥两
目的探讨儿童青少年注意缺陷多动障碍(ADHD)合并品行障碍(CD)的流行特征。方法采用多阶段随机抽样方法,参照美国精神障碍诊断和统计工作手册第四版的注意力缺陷多功能障碍诊
纳米白炭黑作为填料单独掺入天然胶乳基质,通过共硫化法制备了相应的纳米复合材料。测定了力学性能,并与相应的宏观胶乳-白炭黑复合材料比较。研究结果显示,当在胶乳基质中用
中国水利部长江水利委员会、中欧流域管理项目办等单位与机构的50余名中外嘉宾和代表出席了第四届长江论坛“流域综合管理理论与实践”分论坛,与会嘉宾围绕分论坛设置的4个议
威海最大的优势是环境。近1000公里海岸线上,分布着大小100多个岛屿、70多处天然海水浴场、10多处地下温泉和众多港湾,我国最大的天鹅栖息地天鹅湖、“天下第一滩”银滩等风
文章介绍了昆都仑水库的基本情况,分析水库泥沙淤积问题,提出延缓泥沙淤积速度及防治淤积的措施。 This article introduces the basic situation of Qindulun Reservoir, a
目的 了解导入外源性人类全长雌激素受体(ER)β cDNA后,卵巢透明细胞癌细胞系ES-2生长情况和细胞周期的变化.方法 将带有Erβ cDNA的质粒pRSV-Erβ和对照空质粒pRSV分别转染ES-2细胞(分别命名为ES-pRSV-Erβ、ES-pRSV细胞),RT-PCR和蛋白印迹法检测ERβmRNA和蛋白的表达情况,四甲基偶氮唑蓝法、流式细胞仪监测ES-2、ES-pRSV、ES-pRSV-E
利用钢渣对模拟聚驱采油废水进行深度处理,依靠吸附作用去除水中的HPAM。考察了钢渣粒径、搅拌速度、pH以及吸附时间对HPAM去除率的影响,进行了吸附等温线和吸附热力学分析,