高密度ポリエチレンの力学的および流動光学的性質の時間-温度重ね合わせにおける垂直移動の機構について (レオロジー(特集))

概要

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To find out the true causes for the increase in birefringence and the decrease in relaxation modulus for high density polyethylene with rising temperature, measurements were made of the changes in its crystalline structure as well as in its thermal, viscoelastic, and rheo-optical properties with temperature, employing several techniques such as DSC, DLI, infrared dichroism, X-ray diffraction, NMR, and so on. The values in degree of crystallinity obtained from the DSC fusion curve, density, and IR absorbances coincide very well, and show almost no divergence till about 80°C. The optical vertical shift factor pT can be related to the ratio of the orientation function for the crystal c-axis at an arbitrary temperature to that at the reference temperature, fε/fε0. The mechanical vertical shift factor bT, on the other hand, is associated with the variation with temperature, not of the degree of crystallinity, but of the mobility of molecular chains as determined by the NMR technique.
公益社団法人日本材料学会の論文