The combination of fluctuation-assisted crystallization and interface-assisted crystallization in a crystalline/crystalline blend of poly(ethylene oxide) and poly(ε-caprolactone)
The combination of fluctuation-assisted crystallization and interface-assisted crystallization in a crystalline/crystalline blend of poly(ethylene oxide) and poly(ε-caprolactone)
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DOI：
10.1007/s00396-013-3146-z
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发表时间：
2014-04-01
影响因子：
2.4
通讯作者：
Zhao, Xiuxiu
中科院分区：
文献类型：
--
作者：
Huo, Hong;Guo, Caixia;Zhao, Xiuxiu
用光学显微镜（OM）和差示扫描量热法（DSC）研究了聚氧化乙烯（PEO）和聚己内酯（PCL）在PEO/PCL共混体系中的成核和结晶行为。在等温或非等温结晶过程中，当相邻PEO处于熔融状态时，PCL优先在PEO/PCL界面处成核;相邻PEO结晶后，更多的PCL晶核在PEO晶体表面形成。然而，PEO结晶正常，没有界面成核发生在共混物中。液-液相分离引起的浓度波动通过相互扩散和可能的链段取向诱导PEO和PCL链的运动。取向的PEO链段有助于PCL的成核，PEO的异相成核能力随PEO链的取向而增强。取向的PCL链段对PEO没有异相成核能力。推测PEO/PCL共混体系中PCL的界面成核遵循“波动辅助结晶”和“界面辅助结晶”机制的组合。
The nucleation and crystallization of poly(ethylene oxide) (PEO) and poly(epsilon-caprolactone) (PCL) in the PEO/PCL blends have been investigated by means of optical microscopy (OM) and differential scanning calorimetry (DSC). During the isothermal or nonisothermal crystallization process, when the adjacent PEO is in the molten state, PCL nucleation preferentially occurs at the PEO and PCL interface; after the crystallization of the adjacent PEO, much more PCL nuclei form on the surface of the PEO crystal. However, PEO crystallizes normally and no interfacial nucleation occurs in the blend. The concentration fluctuation caused by liquid-liquid phase separation (LLPS) induces the motion of PEO and PCL chains through interdiffusion and possible orientation of chain segments. The oriented PEO chain segments can assist PCL nucleation, and the heterogeneous nucleation ability of PEO increases with the orientation of PEO chains. Oriented PCL chain segments have no heterogeneous nucleation ability on PEO. It is postulated that the interfacial nucleation of PCL in the PEO/PCL blend follows the combination of "fluctuation-assisted crystallization" and "interface-assisted crystallization" mechanisms.