成纤过程中PAN纤维分子链构象的转变
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摘要
利用傅里叶变换红外光谱分析、差示扫描量热分析和动态热机械分析等测试方法对不同等规度PAN样品及成纤过程不同阶段PAN纤维的分子链构象转变行为进行了研究。结果表明:PAN纤维存在两个玻璃化转变点,即a_1转变和a_2转变。随着纺丝过程的进行,纤维中PAN大分子的31螺旋链构象统计量下降,平面锯齿构象统计量增加,低能量构象向高能量构象转变。热环境因素在影响大分子构象重排过程中更加有效。
Fourier transform infrared spectra (FTIR),differential scanning calorimetry (DSC) and dynamic thermomechanical analysis (DMA) were used to investigate the changes in the molecular chain conformation of PAN samples with different isotacticities and PAN fibers in different stages of wet-spinning process. The results show that PAN fiber has two glass transition temperatures corresponding to α_1 and α_2 conformation transition. Statistically,with the decrease of 31 helix confirmation content,the zigzag confirmation content,which has higher potential energy,increases in the wet-spinning process. Thermal effect has greater influence on the conformation transition of macromolecular structure.
Fourier transform infrared spectra (FTIR),differential scanning calorimetry (DSC) and dynamic thermomechanical analysis (DMA) were used to investigate the changes in the molecular chain conformation of PAN samples with different isotacticities and PAN fibers in different stages of wet-spinning process. The results show that PAN fiber has two glass transition temperatures corresponding to α_1 and α_2 conformation transition. Statistically,with the decrease of 31 helix confirmation content,the zigzag confirmation content,which has higher potential energy,increases in the wet-spinning process. Thermal effect has greater influence on the conformation transition of macromolecular structure.
引文
[1]张旺玺.聚丙烯腈基碳纤维[M].上海:东华大学出版社,2005.1-190.
[2]贺福.碳纤维及其应用技术[M].北京:化学工业出版社,2004.2-254.
[3]A.GUPTA,I.R.HARRISON.New Aspects In The Oxidative Stabilization Of Pan-Based Carbon Fibers,Carbon,1996,34(11):1427-1445.
[4]MASATOMO MINAGAWA,KAZUYUKI MIYANO,MASA-HIKO TAKAHASHI,et al.Infrared Characteristic Absorption Bands of Highly Isotactic Poly(acrylonitrile)[J].Macromolecules,1988,21:2387-2391.
[5]殷敬华,莫志深.现代高分子物理学[M].科学出版社,2001.
[6]DAISUKE SAWAI,TETSUO KANAMOTO,ROGER S.PORTER.Differential Scanning Calorimetry Evidence for the Existence of a First-Order Thermal Transition in Ultraoriented at-Poly(acrylonitrile)[J].Macromolecules,1998,31,2010-2012.
[7]KESHAV V.DATYE.Spinning of PAN-fiber:Part III:Wet spinning[J].Synthetic Fibers,1996(4):11-19.
[2]贺福.碳纤维及其应用技术[M].北京:化学工业出版社,2004.2-254.
[3]A.GUPTA,I.R.HARRISON.New Aspects In The Oxidative Stabilization Of Pan-Based Carbon Fibers,Carbon,1996,34(11):1427-1445.
[4]MASATOMO MINAGAWA,KAZUYUKI MIYANO,MASA-HIKO TAKAHASHI,et al.Infrared Characteristic Absorption Bands of Highly Isotactic Poly(acrylonitrile)[J].Macromolecules,1988,21:2387-2391.
[5]殷敬华,莫志深.现代高分子物理学[M].科学出版社,2001.
[6]DAISUKE SAWAI,TETSUO KANAMOTO,ROGER S.PORTER.Differential Scanning Calorimetry Evidence for the Existence of a First-Order Thermal Transition in Ultraoriented at-Poly(acrylonitrile)[J].Macromolecules,1998,31,2010-2012.
[7]KESHAV V.DATYE.Spinning of PAN-fiber:Part III:Wet spinning[J].Synthetic Fibers,1996(4):11-19.