Strain-induced crystallization of natural rubber as studied by high-resolution solid-state 13C NMR spectroscopy
Strain-induced crystallization of natural rubber as studied by high-resolution solid-state 13C NMR spectroscopy
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通过高分辨率固态 13C NMR 光谱研究天然橡胶的应变诱导结晶
DOI：
10.1016/j.polymer.2004.04.064
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发表时间：
2004-06-21
期刊：
影响因子：
4.6
通讯作者：
Chen, Q
中科院分区：
文献类型：
--
作者：
Lin, WX;Bian, MH;Chen, Q
对未拉伸和原位拉伸的天然橡胶样品进行了一系列高分辨率固态C-13 NMR实验。从C-13 CP/MAS谱中发现，天然橡胶在室温下确实形成小晶体，尽管结晶度很小。此外，从C-13 DD/MAS光谱中发现，结晶信号随着拉伸比的增加而增加。首次测定了原位拉伸天然橡胶的C-13自旋-晶格弛豫时间（T-1）和H-1自旋-自旋弛豫时间（T-2），进一步证实了拉伸和未拉伸天然橡胶样品中均存在晶体的结论。定量C-13 NMR测量表明，当拉伸比达到约2.0时发生应变诱导结晶，并且我们的天然橡胶样品在拉伸时的最大结晶度可以高达19.3%。(C)2004爱思唯尔有限公司保留所有权利。
A series of high-resolution solid-state C-13 NMR experiments were performed on both unstretched and in situ stretched natural rubber samples. From the C-13 CP/MAS spectra, it was found that natural rubber does form small crystals at room temperature though the degree of crystallinity is very small. Furthermore, from the C-13 DD/MAS spectra, the crystalline signals were found to increase with the increase of draw ratio. C-13 spin-lattice relaxation time (T-1) and H-1 spin-spin relaxation time (T-2) of in situ stretched natural rubber were measured for the first time, which provided further evidences for the conclusion that there exist crystals in both stretched and unstretched natural rubber samples. Quantitative C-13 NMR measurements indicated that strain-induced crystallization occurs when the draw ratio reaches about 2.0 and the maximum crystallinity of our natural rubber samples can be as high as 19.3% upon stretching. (C) 2004 Elsevier Ltd. All rights reserved.