Fractionation and Molecular Weight of Rubber and Gutta-Percha
Fractionation and Molecular Weight of Rubber and Gutta-Percha
复制标题
橡胶和古塔胶的分级和分子量
DOI：
10.5254/1.3546589
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发表时间：
1941
影响因子：
1.5
通讯作者：
H. Peters
中科院分区：
文献类型：
--
作者：
A. Kemp;H. Peters
摘要1.蒸发乳胶膜和玻利维亚细帕拉含有约62%的氯仿可溶部分，而绉和烟片的可溶部分约为86%，这些溶胶含有低聚合物和“树脂”，平均分子量约为130，000至180，000，可溶性较强的类型具有较低的值。2.采用扩散法和沉淀法对R. C. M. A.起皱，并且以下数据表明分离的可溶性烃级分的大致组成和分子量范围：3.通过X射线和粘度研究判断，绉的氯仿不溶性部分含有非线性类型的烃。这些方法表明，氨保存胶乳膜的氯仿不溶性部分含有极高分子量的橡胶烃，其易于取向以给出橡胶的规则X射线结晶图案。4.新鲜采出的胶乳中含有大量的石油醚可溶性胶乳。
Abstract 1. Evaporated latex films and Bolivian fine para contain a chloroform-soluble fraction of about 62 per cent, whereas the soluble portion of crepe and smoked sheets is about 86 per cent. The average molecular weight of these sols, which contain the low polymers and “resin”, range from about 130,000 to 180,000, the more soluble type having the lower value. 2. Diffusion and precipitation methods were employed to fractionate R. C. M. A. crepe, and the following data indicate the approximate composition and molecular weight range of the soluble hydrocarbon fractions separated: 3. The chloroform-insoluble portion of crepe contains a nonlinear type of hydrocarbon, judged by x-ray and viscosity studies. These methods show that the chloroform-insoluble portion of ammonia-preserved latex films contain extremely high-molecular rubber hydrocarbon which is easily oriented to give the regular x-ray crystalline pattern for rubber. 4. Freshly tapped latex contains a large proportion of petroleum-ether-soluble fr...