Analysis of multiple melting behavior of spherulites comprising ring-band shell/ringless core in polymorphic poly(butylene adipate)
Analysis of multiple melting behavior of spherulites comprising ring-band shell/ringless core in polymorphic poly(butylene adipate)
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DOI：
10.1002/polb.21423
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发表时间：
2008-05-01
影响因子：
--
通讯作者：
Wu, Ming Chien
中科院分区：
文献类型：
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作者：
Woo, E. M.;Yen, Kai Cheng;Wu, Ming Chien
通过设计复合核-壳球晶的方法，对聚己二酸1，4-丁二醇酯（PBA）的环带球晶形态、晶体、多晶型和复杂的熔融行为进行了深入的解释。通过加热到52 ℃并在该温度下保持30分钟退火，可以通过熔融剥离核，并且具体地对环-壳部分（通过受控熔融剥离无环核）的分析证明最高熔融峰（在55-57 ℃下的P-4）可能与环带薄片的熔融有关。此外，PBA中异常复杂的多重熔融可以归因于所有三种广泛提出的机制：（1）结晶PBA中预先存在的多种类型的层状结构，（2）扫描/加热诱导的重熔/重组，和（3）双晶胞的多态性。此外，这项研究还表明，无论是交替的边缘和平坦的机制或替代的起源，在环带状壳内的消光环可以是所有单一的a-晶体形式，无论是最初的或后加热温度诱导的转变。因此，多晶型PBA中的晶型类型（α或β）主要与结晶温度（Tc = 28或35 ℃）相关，而不太可能与层状取向（平贴或侧贴）相关。(c)2008 Wiley Periodicals，Inc.
In-depth interpretation of ring-banded spherulitic morphology, crystals, polymorphism, and complex melting behavior in poly(1,4-butylene adipate) (PBA) were analyzed via a procedure of designing composite core-shell spherulites, in which two lamellar patterns (ring-band vs. ringless) were packed by subjecting to crystallization at two-step temperature schemes with specific temperatures and times. By heating to 52 degrees C and holding at that temperature for 30 min annealing, the core can be stripped off by melting, and analysis specifically on the ring-shell portion (with the ringless core stripped by controlled melting) proves that the highest melting peak (P-4 at 55-57 degrees C) is likely associated with melting of the ring-band lamellae. Furthermore, the unusually complex multiple melting in PBA can be attributed to all three widely proposed mechanisms: (1) multiple types of lamellae preexisting in crystallized PBA, (2) scan/heating induced remelting/reorganization, and (3) polymorphism of dual crystal cells. In addition, this study evidently shows that the extinction rings within the ring-banded shell, regardless of alternate edge-on and flat-on mechanism or alternative origins, can be of all singly a-crystal form, either initially or upon post-heating temperature-induced transformation. Thus, the type of crystal forms (alpha or beta) in polymorphic PBA is mainly associated with temperature of crystallization (T-c = 28 or 35 degrees C), and not likely with lamellar orientation (flat-on or edge-on). (c) 2008 Wiley Periodicals, Inc.