Solution Crystallization Behavior of Linear and Star-shaped Poly(ethylene glycol)-b-Poly(ε-caprolactone) Block Copolymers简 |
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引用本文: | 王宗宝,顾群.Solution Crystallization Behavior of Linear and Star-shaped Poly(ethylene glycol)-b-Poly(ε-caprolactone) Block Copolymers简[J].高分子科学,2013,31(12):1717-1724. |
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作者姓名: | 王宗宝 顾群 |
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作者单位: | [1]Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China [2]School of Petrochemical Technology, Lanzhou University of Technology, Lanzhou 730050, China. [3]Institute of Material Engineering, Ningbo University of Technology, Ningbo 315016, China |
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基金项目: | This project was financially supported by the National Natural Science Foundation of China (Nos. 21004073 and 51003117), Zhejiang Province Innovative Research Team (No. 2009R50013), Ningbo Innovative Research Team (No. 2009B21008), Ningbo Key Lab of Polymer Materials (No. 2010A22001), Zhejiang Provincial Natural Science Foundation (No. Y4100517). |
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摘 要: | Lamellar crystals of diblock, triblock and four-arm poly(ethylene glycol)-b-poly(ε-caprolactone) (PEG-b-PCL) crystalline-crystalline copolymers were successfully obtained from their solution. Morphology and structure of lamellar crystals of crystalline-crystalline copotymers were investigated using tapping-mode atomic force microscopy (AFM) and selected area electron diffraction (SAED). All of these samples showed the truncated-lozenge multilayer basal shapes with central screw dislocation or central stack, which were all obtained simultaneously from the oil bath. The diffraction pattern of PEG block lamellar crystal is attributed to the (120) diffracting planes and the pattern of PCL block lamellar crystal is attributed to the (1 I0) diffracting planes and (200) diffracting planes according to the SAED results. Four (110) crystal growth planes and two (200) crystal growth planes are discovered for the PCL blocks, but the (120) crystal growth planes of PEG blocks are hided in the figure of AFM. The crystalline structure of the four-arm copolymers (FA) is more disorder and confused than that of the diblock (DI) copolymer and the striated fold surface structures of lamellar crystals of four-arm copolymers (FA) are smoother than these of linear analogues, owing to the confused crystallization of blocks caused by the mutual restriction of blocks and the hindrance of the dendritic cores. In addition, the aspect ratio of FA is greater than that of the others. It is hypothesized that there are two reasons for the change of aspect ratios. First, the (200) diffracting planes of PCL crystals grew slowly compared to their (110) diffracting planes because of difference in the energy barrier. Secondly, edge dislocations on the (200) diffracting planes are also responsible for the variation of the aspect ratio. Consequently, the crystalline defects are augmented by the competing blocks crystallized simultaneously and the hindrance of the dendritic cores.
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关 键 词: | 嵌段共聚物 结晶行为 ε-己内酯 乙二醇 线性 溶液 选区电子衍射 原子力显微镜 |
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