CRYSTALLINITY AND FUSION OF LOW-MOLECULAR WEIGHT ALPHA, OMEGA-ALKOXY-POLY(ETHYLENE OXIDE) - METHOXY TO OCTADECOXY END-GROUPS
CRYSTALLINITY AND FUSION OF LOW-MOLECULAR WEIGHT ALPHA, OMEGA-ALKOXY-POLY(ETHYLENE OXIDE) - METHOXY TO OCTADECOXY END-GROUPS
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DOI：
10.1016/0032-3861(78)90224-0
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发表时间：
1978-01-01
期刊：
影响因子：
4.6
通讯作者：
BOOTH, C
中科院分区：
文献类型：
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作者：
COOPER, DR;LEUNG, YK;BOOTH, C
制备了α，ω-ALK氧基聚环氧乙烷样品，其氧乙烯内段为70~150个链原子，端段为C_1(甲氧基)~C_(18)(十八氧基)。用几种实验方法研究了它们的晶体结构和熔融行为。聚合物结晶成晶层和非晶层交替的堆积结构。亚甲基链在非晶层中，与氧乙烯内嵌段的相当一部分(约0.2)一起。结晶层包含延伸或折叠的氧乙烯链，这取决于内层和端层的相对长度。熔点大致与亚甲基嵌段长度无关(延长链晶体)，或随亚甲基嵌段长度增加(折叠链晶体)。这种熔融行为是两种重要效应的结合：纤毛进入非晶层的构象限制以及熔体中亚甲基和氧乙烯链的混合。
Samples of α,ω-alk oxy-poly (ethylene oxide) with oxyethylene inner blocks of 70 to 150 chain atoms and end blocks ranging from C1(methoxy) to C18(octadecoxy) have been prepared and characterized. Several experimental methods have been used to investigate their crystalline structure and melting behaviour. The polymers crystallize into stacked structures in which crystalline and non-crystalline layers alternate. The methylene chains are in the non-crystalline layers together with a significant fraction (about 0.2) of the oxyethylene inner block. The crystalline layers contain extended or folded oxyethylene chains, depending upon the relative lengths of the inner and end blocks. The melting points either are roughly independent of methylene block length (extended-chain crystals) or increase with methylene block length (folded-chain crystals). This melting behaviour is explained by a combination of two important effects: conformational restriction of the cilia emerging into the non-crystalline layer and mixing of the methylene and oxyethylene chains in the melt.