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首页> 外文期刊>Journal of Applied Polymer Science >Fast Crystallization of Liquid Crystalline Copolyesters Based on Poly(ethylene terephthalate)
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Fast Crystallization of Liquid Crystalline Copolyesters Based on Poly(ethylene terephthalate)

机译：基于聚对苯二甲酸乙二醇酯的液晶共聚酯的快速结晶

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摘要

Crystallization of a series of liquid crystalline copolyesters prepared from p-hydroxybenzoic acid (HBA), hydroquinone (HQ), terephthalic acid (TA), and poly(eth- ylene terephthalate) (PET) was investigated by using differential scanning calorimetry (DSC). It was found that these copolyesters are more crystalline than copolyesters prepared from PEr~d HBA. Insertion of HQ-TA disrupts longer rigid-rod sequences formed by HBAand thus enhances molecular motion and increases the crystallization rate. The effects of additives on the crystallization of the copoly~,sters were also studied. Sodium benzoate (SB) and sodium acetate (SA) increase the crystallization rate of the copolyesters at1ow temperature, but not at high temperature. It is most likely that liquid crystalline copolyesters do not need nucleating agents, and small aggregates of local-oriented rodlike segments in nematic phase could act as primary nuclei. Chain scission of the copolyesters caused by the reaction with the nucleating agents was proved by the determination of intrinsic viscosity and by the IR spectra. Diphenyl- ketone (DPK) was shown to effectively promote molecular motion of chains, leading to an increase in the crystallization rate at low temperature, but it decreased tl:le crys- tallization rate at..high temperature.
机译：使用差示扫描量热法（DSC）研究了由对羟基苯甲酸（HBA），对苯二酚（HQ），对苯二甲酸（TA）和聚对苯二甲酸乙二酯（PET）制备的一系列液晶共聚酯的结晶。已发现这些共聚酯比由PEr-d HBA制备的共聚酯更结晶。 HQ-TA的插入破坏了由HBA形成的更长的刚性棒序列，从而增强了分子运动并提高了结晶速率。还研究了添加剂对共聚酯结晶的影响。苯甲酸钠（SB）和乙酸钠（SA）在较低温度下可提高共聚酯的结晶速率，但在高温下则不会。液晶共聚酯很可能不需要成核剂，而向列相中局部取向的棒状链段的小聚集体可以充当主核。通过测定特性粘度和红外光谱证明了与成核剂反应引起的共聚酯的断链。研究表明，二苯甲酮（DPK）能有效地促进链的分子运动，从而导致低温下结晶速率的增加，但在高温下却降低了结晶速率。

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