液体聚异戊二烯的结构表征

Structure Characterization of Liquid Polyisoprene

通过傅立叶变换红外光谱、核磁共振、不饱和度测定、凝胶渗透色谱、热重分析和动态流变分析等手段对液体聚异戊二烯(LIR-50)的结构及其基本性质进行了研究。结果表明,LIR-50的链节化学组成与天然橡胶完全相同,但二者的空间结构有明显区别。LIR-50的顺-1,4、反-1,4和3,4结构含量分别为70.8%、24.4%、4.8%,而天然橡胶的顺-1,4结构高达98%。LIR-50的数均分子量为42000,多分散指数为1.24,其动态粘度对温度敏感,对剪切速率不敏感。

The structure and properties of liquid polyisoprene （LIRSO）, a new type of processing aid for rubber compounds, were characterized by Fourier transform infrared spectroscopy （ FTIR）, nuclear magnetic resonance （^1H-NMR）, determination of unsaturation degree, gel permeation chromatography （GPC）, thermal gravimetric analysis （TGA） and dynamic theology analysis. The results showed that the chemical composition of LIR.50 is identical with natural rubber, however, the stereo structure of both polymers has obvious differences. The contents of cis-1,4, trans-1,4 and 3,4 structure of LIR-50 are 70. 8%, 24. 4% and 4.8%, respectively, but natural rubber possesses more than 98% of cis-1,4 isoprene structure. The molecular weight Mn of LIR-50 is 42000, and its distribution index is 1.24. The dynamic viscosity of LIR50 is temperature sensitive, but not sensitive to shear rate.