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Dynamic Rheological Studies of Poly(p-phenyleneterephthalamide) and Carbon Nanotube Blends in Sulfuric Acid
State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, Shanghai 201620, China
National Renewable Energy Laboratory, Golden, CO 80401, USA
* Authors to whom correspondence should be addressed.
Received: 11 February 2010; in revised form: 17 March 2010 / Accepted: 18 March 2010 / Published: 31 March 2010
Abstract: We have studied the dynamic scanning of liquid-crystalline(LC) poly(p-phenyleneterephthalamide) sulfuric acid (PPTA-H2SO4) solution, and its blend with single-walled carbon nanotubes (SWNTs), by using a flat plate rotational rheometer. The effects of weight concentration and molecular weight of PPTA, as well as operating temperature, on dynamic viscoelasticity of the PPTA-H2SO4 LCsolution system are discussed. The transition from a biphasic system to a single-phase LC occurs in the weight concentration range of SWNTs from 0.1% to 0.2%, in which complex viscosity reaches the maximum at 0.2 wt% and the minimum at 0.1 wt%, respectively, of SWNTs. With increasing SWNT weight concentration, the endothermic peak temperature increases from 73.6 to 79.9 °C. The PPTA/SWNT/H2SO4 solution is in its plateau zone and storage modulus (G´) is a dominant factor within the frequency (ω) range of 0.1–10 rad/s. As w increases, the G´ rises slightly, in direct proportion to the w. The loss modulus (G´´) does not rise as a function of ω when ω < 1 s−1, then when ω > 1 s−1 G´´ increases faster than G´, yet not in any proportion to the ω.
Keywords: liquid crystalline (LC) solution; single-walled carbon nanotubes (SWNTs); rheology
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Cao, Y.; Liu, Z.; Gao, X.; Yu, J.; Hu, Z.; Liang, Z. Dynamic Rheological Studies of Poly(p-phenyleneterephthalamide) and Carbon Nanotube Blends in Sulfuric Acid. Int. J. Mol. Sci. 2010, 11, 1352-1364.
Cao Y, Liu Z, Gao X, Yu J, Hu Z, Liang Z. Dynamic Rheological Studies of Poly(p-phenyleneterephthalamide) and Carbon Nanotube Blends in Sulfuric Acid. International Journal of Molecular Sciences. 2010; 11(4):1352-1364.
Cao, Yutong; Liu, Zhaofeng; Gao, Xianghua; Yu, Junrong; Hu, Zuming; Liang, Ziqi. 2010. "Dynamic Rheological Studies of Poly(p-phenyleneterephthalamide) and Carbon Nanotube Blends in Sulfuric Acid." Int. J. Mol. Sci. 11, no. 4: 1352-1364.