1HNMR测定含氢硅油含氢量及分子量

以高含氢硅油、八甲基环四硅氧烷和六甲基二硅氧烷为原料,在浓硫酸催化作用下通过调聚反应制备了一系列不同规格的低含氢硅油。并通过1H NMR（以二氧六环为内标物,以氘代氯仿为溶剂）表征了该含氢硅油,由特征峰的面积比计算出了其含氢量,并与化学方法测定的含氢量进行了对比,结果表明两者间相对偏差均小于±1.9%。同时,此方法还可以求得含氢硅油链段中不同结构的链段比,从而求得含氢硅油的分子量;结合特性粘度的测定,求得含氢硅油的K值为4.21×10-5L/g,α值为0.83。K,α值不受含氢量的影响,且与文献中的值一致,表明用1H NMR测定含氢硅油分子量是可行的。该方法具有操作简单、省时、准确、可靠、所需样品量少等优点。

Determination of Content of Hydrogen and Molecular Weight in Hydrogen Silicone Oil by 1H NMR

A series of low hydrogen silicone oil were synthesized with high hydrogen silicone oil,octamethylcyclotetrasiloxane（D4） and hexamethyldisiloxane（MM） as starting materials and concentrated sulfuric acid as catalyst.The polyhydrosiloxane was characterized by 1H NMR with CDCl3 as solvent and dioxane as internal standard.The content of hydrogen was calculated from ratio of characteristic peak area.Compared with the content of hydrogen obtained by chemical method,the relative deviation between the both methods was less than ±1.9%.The chain segment ratio of hydrogen silicone oil was also obtained by 1H NMR,then the molecular weight of hydrogen silicone oil could be calculated.Combined with the determination of intrinsic viscosity,the K=4.21×10-5L/g and α=0.83 of the polymers were calculated.The values of K,α were consistent with literature values,that had no effect on the content of hydrogen.The determination of molecular weight of hydrogen silicone oil by 1H NMR is feasible.This method is simple,time-saving,accurate,reliable,required less sample and so on.