充油SEBS的结构、力学性能和紫外辐照稳定性

自制了一种中间基的苯乙烯-乙烯/丁烯-苯乙烯三嵌段共聚物(SEBS)弹性体用填充油,并从分子结构及微相结构上分析了线型和星型SEBS充油体系的力学性能、紫外辐照稳定性与其结构的关系。通过小角X射线散射(SAXS)、透射电子显微镜(TEM)表征了SEBS充油体系的微观结构,揭示了SEBS分子结构是影响充油体系微观结构的主要因素,且软硬段电子密度差以及PS相间距越大,SEBS的微相分离程度越高。结合Instron万能材料试验机的测试结果,发现SEBS微相分离程度高有利于充油体系力学性能的提高。通过傅里叶红外光谱(FTIR)研究了经紫外辐照后SEBS体系的化学结构变化,结果显示,经紫外辐照后的体系均在1700~1740 cm-1、1800 cm-1附近出现吸收峰,且吸收峰强度越大,力学性能下降得越快,表明氧化降解是造成SEBS体系力学性能下降的主要因素。

Structure,Mechanical Properties and UV Stability of Oil-extended SEBS

An intermediate group of styrene-ethylene/butylene-styrene triblock copolymer(SEBS)elastomer filler oil was prepared.The relationship among the mechanical properties,UV radiation stability,and structure of linear SEBS and star SEBS was studied from the microphase structure and molecular structure.Small-angle X-ray scattering(SAXS)and transmission electron microscopy(TEM)were used to characterize the microstructure.It is revealed that the molecular structure of SEBS is the main factor that affects the microphase structure.The greater the electron density difference between the soft and hard segments,the PS phase size and phase spacing,the higher the degree of microphase separation of SEBS could be obtained.Combining with the test results of the Instron material testing machine,it is found that the high degree of SEBS microphase separation is beneficial to the improvement of the mechanical properties of the oil-extended system.Fourier transform infrared spectroscopy(FTIR)was used to study the chemical constitution changes of the system after the irradiation.The FTIR absorption peaks appear around 1700~1740 cm-1,1800 cm-1.The absorption peak intensity is large,and the mechanical properties decrease quickly,indicating that the unsaturated carbonyl group generated by oxidative degradation is the main factor that causes the decrease of the mechanical properties.