Crystallization and Transient Mesophase Structure in Cold-Drawn PET Fibers
Crystallization and Transient Mesophase Structure in Cold-Drawn PET Fibers
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DOI：
10.1021/ma034694i
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发表时间：
2003-12
期刊：
影响因子：
5.5
通讯作者：
J. Keum;Jinmo Kim;Sang Man Lee;H. Song;Yang-Kug Son;Jong-In Choi;S. Im
中科院分区：
文献类型：
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作者：
J. Keum;Jinmo Kim;Sang Man Lee;H. Song;Yang-Kug Son;Jong-In Choi;S. Im
采用同步加速器广角x射线衍射、红外光谱和热力学分析研究了冷拔PET纤维的瞬态结构和结晶行为。纺丝后的PET纤维被机械冷拉伸至断裂点，拉伸后的PET纤维在应力-应变曲线上超过应变硬化点时呈现瞬态层状结构。有证据表明，瞬态层结构中存在倾斜的PET链，因此存在近晶C中间相。层内链与纤维轴的倾斜角为6°。随着结晶的进行，倾斜角度迅速减小。x射线衍射、红外吸收和热力学分析结果表明定向PET链存在两阶段结晶。第一阶段结晶（80 ~ 100℃）是由包括中间相在内的高取向链束形成的，第二阶段结晶（14℃以上）是由无序链束或无取向链束形成的。
Transient structure and crystallization behaviors in cold-drawn PET fibers were studied by synchrotron wide-angle X-ray diffraction, IR spectroscopy, and thermomechanical analysis. As-spun PET fibers were mechanically cold-drawn up to the breaking point, and those stretched ones beyond the strain hardening point in the stress−strain curve exhibited the transient layer structure. Evidence suggesting the tilted PET chains within the transient layer structure, and therefore the smectic C mesophase, was discussed. The tilt angle of the chains within the layer was 6° against the fiber axis. The tilt angle, however, decreased rapidly with the crystallization. Results of X-ray diffraction, IR absorbance, and thermomechanical analysis suggested two-stage crystallization in oriented PET chains. Bundles of highly oriented chains including the mesophase were responsible for the first stage crystallization (80−100 °C), but those of less ordered or nonoriented chains were for the second stage crystallization beyond 14...