Proton Magnetic Resonance Studies on Natural Rubber. II. Line Shape and T1 Measurements
Proton Magnetic Resonance Studies on Natural Rubber. II. Line Shape and T1 Measurements
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天然橡胶的质子磁共振研究。
DOI：
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发表时间：
1957
期刊：
影响因子：
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通讯作者：
D. Woessner
中科院分区：
文献类型：
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作者：
H. S. Gutowsky;A. Saika;M. Takeda;D. Woessner
质子磁共振吸收测量已在未固化的橡胶树，橡胶，珊瑚橡胶以及硫化样品高达9%的结合硫的样品。通过在-190至150°C之间的温度下观察线形和自旋晶格弛豫时间来研究链段的运动。几种类型的数据显示了具有给定组合硫的硫化样品的不同分子迁移率，但是通过将具有不同比例的粗硫的混合物固化不同时间来制备。未固化的橡胶树样品的线宽研究作为热历史的函数表明，分子的流动性随着结晶度的增加而降低。在未固化的橡胶树，橡胶，珊瑚橡胶的解决方案的高分辨率研究解决了化学位移。T1测量，包括在20和28兆赫兹/秒的观测未固化的橡胶树和橡胶，表现出系统的偏差从BPP理论。的偏差的意义进行了讨论。
Proton magnetic resonance absorption measurements have been made on samples of uncured Hevea, balata, and Coral rubber as well as on vulcanized samples with up to 9% combined sulfur. The motions of the chain segments were studied by observing line shapes and spin‐lattice relaxation times at temperatures between —190 and 150°C. Several types of data show different molecular mobilities for vulcanized samples with a given combined sulfur but prepared by curing mixes with different fractions of raw sulfur for different times. Line width studies of the uncured Hevea sample as a function of thermal history indicate that the molecular mobility decreases with increasing crystallinity. Chemical shifts were resolved in high resolution studies of solutions of uncured Hevea, balata, and Coral rubber. The T1 measurements, including observations at 20 and 28 Mc/sec on uncured Hevea and balata, exhibit systematic deviations from the BPP theory. The significance of the deviations is discussed.