丁二烯-丙烯腈-异戊二烯三元共聚物的耐低温性能及分子模拟

摘要

The structure characteristics of butadiene-acrylonitrile-isoprene terpolymer (NBIR) and its hydrogenation products (HNBIR) were analyzed by hydrogen nuclear magnetic resonance (1H-NMR) and Fourier transform infrared spectroscopy.The relative molecular mass and glass transition temperature (Tg) were measured by gel permeation chromatography and differential scanning calorimetry.The peak positions of the characteristic peaks of 1H-NMR spectra were analyzed, and the structure and group content of NBIR were calculated quantitatively according to the peak area, and on these basis, the molecular model was constructed by molecular simulation.The cohesion energy density, Tg and semi-decomposition temperature parameters of HNBIR were obtained by molecular dynamics simulation.The results showed that the content of bound acrylonitrile was the main factor that affected the low temperature and oil resistance of HNBIR.The thermal stability improved and low temperature resistance weakened with the increase of hydrogenation degree of HNBIR.The molecular simulation results were in good agreement with the experimental data.%通过核磁共振波谱和傅里叶变换红外光谱分析了丁二烯-丙烯腈-异戊二烯三元无规共聚物(NBIR)及其加氢产物(HNBIR)的结构特征,并以凝胶渗透色谱法和差示扫描量热法测定了其相对分子质量、玻璃化转变温度等结构参数.分析了核磁共振波谱特征峰的峰位并按峰面积定量计算了NBIR的结构组成及基团含量,以此为基础采用分子模拟法构建了NBIR的分子模型,并通过分子动力学方法模拟计算了HNBIR的内聚能密度、玻璃化转变温度、半分解温度等参数.结果表明,HNBIR中的结合丙烯腈含量是影响其耐低温及耐油性能的关键因素,而氢化度的增大使得共聚物的热稳定性得以提高,耐低温性能减弱.分子模拟计算结果与实验测试数据吻合得较好.