Crystalline Phases in Ethylene Copolymers Studied by Solid-State NMR and DSC
Crystalline Phases in Ethylene Copolymers Studied by Solid-State NMR and DSC
复制标题
通过固态 NMR 和 DSC 研究乙烯共聚物中的晶相
DOI：
10.1021/ma1000578
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发表时间：
2010-07-13
期刊：
影响因子：
5.5
通讯作者：
Feng, Jiwen
中科院分区：
文献类型：
--
作者：
Gao, Xiuzhi;Wang, Liying;Feng, Jiwen
结合固体核磁共振和差示扫描量热法，研究了乙烯辛烯和乙烯丁烯共聚物中多种有序相的结构和热性能。三种有序相，即正交相。已发现单斜相和旋转相（或有序流动相）共存于这两种乙烯共聚物中。我们的实验结果表明，慢钉扎固态 CP/MAS C-13 NMR 提供了一种便捷的方法来识别三种不同有序相的 NMR 信号并测量斜方相和单石灰相的 C-13 化学位移张量 C-13 化学位移的测量 张量和磁弛豫时间表明，单斜晶相和斜方晶相具有相似的化学位移各向异性，具有 180 度 hip-hop 段运动。另一方面，旋转相中的化学位移各向异性和段迁移率与斜方晶和单斜晶相不同。DSC Jesuits 表明，室温老化过程中 ms 的低熔点相 变温固态 CP/MAS NMR 谱与慢速旋转后期和 DSC 测量的结合揭示了低熔点相与旋转体结构之间的明显相关性，因此表明室温老化诱导的旋转体形成是具有不同侧基大小的乙烯共聚物的常见现象
The structures and thermal properties of the multiple ordered phases in ethylene octene and ethylene butene copolymers have been studied using a combination of solid-suite NMR and DSC Three types of the ordered phases, namely the orthorhombic. monoclinic, and rotator (or ordered mobile phase), have been found to coexist in these two ethylene copolymers Our experimental results demonstrate that the slow-pinning solid-state CP/MAS C-13 NMR provides a convenient method to discern the NMR signals of the three different ordered phases and to measure the C-13 chemical shift tensors of orthorhombic and mono:lime phases The measurements of C-13 chemical shift tensors and magnetic relaxation times show that monoclinic and orthorhombic crystal phases have similar chemical shift anisotropy with 180 degrees hip-hop segmental movement The chemical shift anisotropy and segmental mobility in the rotator phase, on the other hand, are different from those in the orthorhombic and monoclinic phases DSC Jesuits illustrate that a low-melting-point phase for ms during room-temperature aging and melts at temperature slightly above the room temperature The apparent correlation between the low-melting-point phase and the rotator structure is revealed by a combination of variable-temperature solid-state CP/MAS NMR spectra with a slow-spinning late and DSC measurement It is thus suggested that the rotator formation induced by room-temperature aging is a common phenomenon for the ethylene copolymers with different sizes of side groups