Morphology of oriented linear polyethylene: A study by Raman spectroscopy
Morphology of oriented linear polyethylene: A study by Raman spectroscopy
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取向线性聚乙烯的形态：拉曼光谱研究
DOI：
10.1002/pol.1981.180191002
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发表时间：
1981
期刊：
影响因子：
--
通讯作者：
I. Ward
中科院分区：
文献类型：
--
作者：
G. Capaccio;M. Wilding;I. Ward
测量了取向线性聚乙烯的低频拉曼纵声模振动。定向样品通过拉伸拉伸慢冷和淬火片材来制备，并且包括拉伸比高达30的超高模量材料。在低分子量和中等分子量的样品中清楚地观察到LAM线，拉伸比高达约1.5。15.在所有这些情况下的拉曼光谱已被用来计算整个分布的晶体尺寸。该程序导致数均和重均晶体尺寸的值，其与通过X射线衍射法和凝胶渗透色谱法对蚀刻样品进行的晶体尺寸测定非常一致。在较高的拉伸比下，LAM线的峰值强度减小。这可以归因于晶体厚度分布的变化，与X射线衍射和硝酸蚀刻的数据一致。由于初始形态，样品的分子量，和绘制温度的影响也进行了研究。
Measurements have been made of the low-frequency Raman longitudinal acoustic mode (LAM) vibration in oriented linear polyethylenes. The oriented samples were prepared by tensile drawing of both slow-cooled and quenched sheets, and included ultrahigh-modulus materials from draw ratios up to 30. A LAM line is observed clearly in samples of low and intermediate molecular weight up to draw ratios of ca. 15. In all these cases the Raman spectrum has been used to calculate the whole distribution of crystal sizes. This procedure leads to values of the number-average and weight-average crystal size which are in good agreement with crystal size determinations by x-ray diffractometry and gel permeation chromatography on etched samples. At higher draw ratios the peak intensity of the LAM line is diminished. This can be attributed to a change in the distribution of crystal thicknesses, consistent with data from x-ray diffraction and nitric acid etching. Effects due to initial morphology, sample molecular weight, and draw temperature have also been examined.