Effects of Molecular Structure on Segment Orientation in Poly(diethylsiloxane) Elastomers. 2. NMR Measurements from Uniaxially Stretched Samples
Effects of Molecular Structure on Segment Orientation in Poly(diethylsiloxane) Elastomers. 2. NMR Measurements from Uniaxially Stretched Samples
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DOI：
10.1021/ma010408w
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发表时间：
2001-07
期刊：
影响因子：
5.5
通讯作者：
Ronald C Hedden;H. Tachibana;T. Duncan;C. Cohen
中科院分区：
文献类型：
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作者：
Ronald C Hedden;H. Tachibana;T. Duncan;C. Cohen
用固态2H核磁共振研究了含- CD2CH3基团的端链聚（二乙基硅氧烷）网络的单轴延伸。在非晶状态下，对低延伸比的样品进行了链段取向测量。在较高的延伸比下，可以发生局部相变到中形态“颈”。在不同的延伸比下，用核磁共振探测了颈部的中间相含量和节段取向。通过对一系列不同分子量交联样品的研究，推导出化学交联密度对链段取向的影响。
End-linked poly(diethylsiloxane) networks containing −CD2CH3 groups were studied in uniaxial extension by solid-state 2H NMR. Chain segment orientation was measured for samples at low extension ratios in the amorphous state. At higher extension ratios, a localized phase transition to a mesomorphic “neck” can occur. The mesophase content and segment orientation in the neck region were probed by NMR at various extension ratios. The effects of chemical cross-link density on segment orientation were deduced by studying a series of samples with varying molecular weight between cross-links.