链拓扑结构对嵌段共聚物结晶行为的影响

摘要

The crystallization behavior of two kinds of triblock block copolymers synthesized with equal con-tent of polyethylene glycol(PEG) and almost equal content of polystyrene(PS), namely H-type(PS)2-PEG-( PS) 2( PEG chains linking in the middle of PS chains) and linear PS-PEG-PS( PEG chains linking to the end of PS chains) , were studied comparatively by small-angle X-ray scattering( SAXS) , wide angle X-ray diffrac-tion ( WAXD ) , differential scanning calorimetry ( DSC ) , polarized optical microscopy ( POM ) and other means. It is found that, although the crystal forms of PEGs in copolymers are same, the crystallization tem-perature of the H-type is lower than that of the linear, the thickness of PEG crystal lamella is smaller, and the crystallization rate is slower at the same temperature, which originates from the larger steric hindrance caused by the bifurcation chain structure of H-type copolymer.%通过等量的聚乙二醇(PEG)和聚苯乙烯(PS)合成了H型(PS)2-PEG-(PS)2(PEG链接在PS链的中间)和线型PS-PEG-PS( PEG链接在PS链的一端)三嵌段共聚物，并通过X射线小角散射( SAXS)、 X射线广角衍射( WAXD)、示差扫描量热仪( DSC)和偏光显微镜( POM)等手段研究了其结晶行为，结果表明2种共聚物中PEG的晶型相同，但是H型比线形结晶温度更低， PEG片晶厚度更小，在相同温度下PEG结晶速度更慢，这是由于H型分岔结构引起空间位阻较大所致。