利用紫外光谱、流变、XRD等分析方法,研究了溶液极性对PAN晶态结构形成的影响。研究结果发现,PAN溶液中溶剂的极性能够通过影响溶液中PAN分子链的存在状态,导致相分离后聚合物晶态结构产生差异。随着溶剂极性的增大,溶剂分子与PAN大分子链间的相互作用力增强,溶液特性黏度、表观黏度等依次增大,PAN分子链段逐渐舒展,在相同凝固条件下得到的聚合物结晶度逐渐减小,晶粒尺寸依次增大。
Abstract
The formation of crystalline polyacrylonitrile (PAN) materials is directly influenced by the properties of the precursor PAN solution. In particular, the polarity of the solution can influence the interaction between the various components of the system, and determine the properties of the solution. We have studied the effect of the polarity of PAN solution on the crystallinity of PAN by using UV spectroscopy, rheological measurements, XRD and other analysis methods. The results indicate that the polarity of the solvent can affect the PAN molecular chain conformation, and determine the crystallinity of PAN after phase separation. With increasing polarity of the PAN solutions, the intermolecular forces between solvent and PAN molecules increase, and the intrinsic viscosity [η], apparent viscosity and other parameters of the solution all increased, resulting in the PAN molecular chain being gradually stretched. Higher polarities of PAN solution result in a lower crystallinity and larger crystal size under the same coagulation bath conditions.
关键词
溶液极性 /
分子链构象 /
结晶度 /
晶粒尺寸
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Key words
solution polarity /
conformation of molecular chain /
crystallinity /
crystal size
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参考文献
[1]Zhang W X, Liu J, Wu G. Evolution of structure and properties of PAN precursors during their conversion to carbon fibers[J]. Carbon, 2003, 41: 2805-2812.
[2]Xu Q, Xu L H, Cao W Y, et al. A study on the orientation structure and mechanieal properties of polyacrylontrile precursors[J]. Polymers for Advanced Technologies, 2005, 16: 642-645.
[3]Sobhanipour P, Cheraghi R, Volinsky A A. Thermoporometry study of coagulation bath temperature effect on polyacrylonitrile fibers morphology[J]. Thermochimica Acta, 2011, 518: 101-106.
[4]李常清, 蓝雁, 徐樑华. 凝固条件对PAN初生纤维微结构的影响[J]. 合成纤维工业, 2008, 31(4): 22-24.
Li C Q, Lan Y, Xu L H.Effect of coagulation conditions on microstructure of as-spun PAN fiber[J]. China Synthetic Fiber Industry, 2008, 31(4): 22-24.(in Chinese)
[5]Bahrami S H, Bajaj P, Sen K. Effect of coagulation conditions on properties of poly(acrylonitrile-carboxylic acid) fibers[J]. Journal of Applied Polymer Science, 2003, 89: 1825-1837.
[6]李常清, 杨策宇, 肖阳, 等. 晶态结构对聚丙烯腈(PAN)原丝预氧化反应的影响[J]. 高分子材料科学与工程, 2013, 29(4): 86-88.
Li C Q, Yang C Y, Xiao Y, et al. Effect of crystal structures on pre-oxidation of PAN precursor[J]. Polymer Materials Science and Engineering, 2013, 29(4): 86-88. (in Chinese)
[7]金日光, 华幼卿. 高分子物理[M]. 3版. 北京: 化学工业出版社, 2010.
Jin R G, Hua Y Q. Polymer physics[M]. 3rd ed.Beijing: Chemical Industry Press, 2010. (in Chinese)
[8]程能林. 溶剂手册[M]. 3版. 北京:化学工业出版社, 2002.
Cheng N L. Solvent handbook[M]. 3rd ed. Beijing: Chemical Industry Press, 2002. (in Chinese)
[9]Boom R M, van den Boomgaard T, van den Berg J W A, et al. Linearized cloudpoint curve correlation for ternary systems consisting of one polymer,one solvent and one non-solvent[J]. Polymer, 1993, 34(11):2348-2356.
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脚注
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基金
国家“973”计划(2011CB605602)
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