Chain Mobility in Polymer Systems: on the Borderline between Solid and Melt. 1. Lamellar Doubling during Annealing of Polyethylene
Chain Mobility in Polymer Systems: on the Borderline between Solid and Melt. 1. Lamellar Doubling during Annealing of Polyethylene
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DOI：
10.1021/ma970519o
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发表时间：
1997-12
期刊：
影响因子：
5.5
通讯作者：
S. Rastogi;Ab Anne Spoelstra;Jgp Han Goossens;Pj Piet Lemstra
中科院分区：
文献类型：
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作者：
S. Rastogi;Ab Anne Spoelstra;Jgp Han Goossens;Pj Piet Lemstra
原位小角X射线散射（SAXS）和低频拉曼光谱实验已经进行了研究的流动性和运动的聚合物链退火后的温度范围接近，但低于熔融温度。以超高分子量聚乙烯（UHMWPE）为模型聚合物，采用溶液结晶法制备。溶液结晶膜干燥后可得到规则排列的层状晶体。小角X射线散射研究表明，加热到110 °C以上时，片层厚度（长周期）增加到初始值的两倍。通过透射电子显微镜（TEM）证实了这种量子增加。通过原位低频拉曼光谱，观察到在加热期间，纵向声学（LA）拉曼频率向较低值发生偏移，这指示晶体芯的厚度增加。结合实验观察表明，增稠发生通过相互链重排被…
In-situ small-angle X-ray scattering (SAXS) and low-frequency Raman spectroscopy experiments have been performed to study the mobility and motion of polymer chains upon annealing in a temperature range close to but below the melting temperature. Ultrahigh molecular weight polyethylene, UHMW-PE, was taken as the model polymer, which was crystallized from solution. Regularly stacked lamellar crystals could be obtained after drying the solution-crystallized films. SAXS studies revealed that, upon heating above 110 °C, the lamellar thickness (long period) increases to twice the initial value. This quantum increase was confirmed by transmission electron microscopy (TEM). By means of in-situ low-frequency Raman spectroscopy it was observed that during heating a shift occurs in the longitudinal acoustic (LA) Raman frequency to lower values, indicative of an increase in the thickness of the crystalline core. The combined experimental observations indicate that thickening occurs via a mutual chain rearrangement be...