Rheological behavior during thermotropic gelation of polyacrylonitrile concentrated solutions

【作者】 马彩霞； 闫伟霞； 张莉； 秦宗益； 潘鼎；

【Author】 MA Cai-xia YAN Wei-xia ZHANG Li QIN Zong-yi PAN Ding State Key Laboratory for Chemical Fibers Modification and Polymer Materials,Donghua University,Shanghai 201620,China Research Centre for Analysis and Measurement,Donghua University,Shanghai 201620,China

【机构】 State Key Laboratory for Chemical Fibers Modification and Polymer Materials,Donghua University； Research Centre for Analysis and Measurement,Donghua University；

【摘要】 <正>Dynamic viscoelastic properties of polyacrylonitrile（PAN）/DMSO/H₂O solutions with different H₂O contents were studied as a function of temperature.These PAN solutions gradually became gel with decreasing temperature.The sol-gel transition took place at a critical gel temperature,at which the scaling law of G′（ω）～G″（ω）∝ωⁿ held,allowing an accurate determination of the critical gel temperature by means of the frequency independence of the loss tangent.The gel point of PAN solutions increases with increasing H₂0 content.The scaling exponent n（=0.86）at the gel point is confirmed to be universal for PAN gels,which is independent of temperature,suggesting the similarity of the fiactal structure in the critical PAN gels.更多还原

【Abstract】 Dynamic viscoelastic properties of polyacrylonitrile（PAN）/DMSO/H₂O solutions with different H₂O contents were studied as a function of temperature.These PAN solutions gradually became gel with decreasing temperature.The sol-gel transition took place at a critical gel temperature,at which the scaling law of G′（ω）～G″（ω）∝ωⁿ held,allowing an accurate determination of the critical gel temperature by means of the frequency independence of the loss tangent.The gel point of PAN solutions increases with increasing H₂0 content.The scaling exponent n（=0.86）at the gel point is confirmed to be universal for PAN gels,which is independent of temperature,suggesting the similarity of the fiactal structure in the critical PAN gels.更多还原