用黏度法测定稀土顺丁橡胶的相对分子质量

用黏度法(外推法或一点法)测定了中国石油独山子石化公司研究院中试装置生产的稀土顺丁橡胶(NdBR)的特性黏数(η]),研究了温度、初始浓度对测定结果的影响,最终由Mark-Houwink方程计算其黏均分子量,并与镍系顺丁橡胶(NiBR)进行了比较。结果表明,NdBR的黏均分子量为28.0×104~34.3×104,高于NiBR(24.6×104);用一点法测定NdBR的η]比外推法更简便快捷,二者的相对误差不超过4.0%,因而可用一点法替代外推法进行NdBR黏均分子量的测定。

Determination of relative molecular mass of rare earth-based cis-1,4-polybutadiene rubber by viscosimetry

Intrinsic viscosity(η]) of the rare earth-based cis-1,4-polybutadiene rubber (NdBR) produced by pilot plant of Institute of Dushanzi Petrochemical Company was determinated with viscometry, that was extrapolation method or one-point method. The influences of temperature and initial concentration of NdBR on η] was studied. The viscosity-average molecular mass of NdBR was finally calculated by the Mark-Houwink equation and compared with nickel-based cis-1,4-polybutadiene(NiBR). The results showed that the viscosity-average molecular mass of NdBR was between 28.0×10~4～34.3×10~4, which was higher than that of NiBR(24.6×10~4). One-point method used in determining η] of NdBR was more simple and quick than extrapolation method. The relative error of the two methods was less than 4.0%. So one-point method could replace extrapolation method to determine the viscosity-average molecular mass of NdBR.