Infrared dichroism and visible-ultraviolet dichroism studies on roller-drawn polypropylene and polyethylene sheets
作者:
A. Kaito,
K. Nakayama,
H. Kanetsuna,
期刊:
Journal of Macromolecular Science, Part B
(Taylor Available online 1987)
卷期:
Volume 26,
issue 3
页码: 281-306
ISSN:0022-2348
年代: 1987
DOI:10.1080/00222348708248070
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
The crystal and amorphous orientation functions of polypropylene (PP) and high-density polyethylene (HDPE) sheets, stretched by the roller-drawing technique, were measured by means of infrared dichroism and visible-ultraviolet dichroism. The molecular chains in the crystalline and amorphous regions lined up parallel to the draw direction in the roller-drawing process. At higher draw ratio (λ > 7–13), the crystal orientation function approached a constant value, whereas the amorphous orientation function increased monotonically with draw ratio. Film tilting measurements revealed that the deviation from symmetric uniaxial orientation was small for the roller-drawn HDPE and PP sheets. In the case of HDPE, the fraction of—GTTG—,—4TG—, and—GG—sequences decreased, and that of the trans-rich sequences increased in the roller-drawing process. These changes were interpreted in terms of the Peterlin model. The orientation function calculated from visible-ultraviolet dichroism decreased greatly with decreasing length of solute (dye) molecules. The reasons for this phenomenon are discussed.
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