Abstract
The very high dope viscosity of concentrated dope of poly[acrylonitrile-co-(methyl acrylate)-co-(itaconic acid)] (with Mv = 10.67 × 105g mol−1) in DMF could be diminished significantly by the addition of oxalic acid (OXA). The change in steady shear rheological behaviour caused by OXA has been analysed for the dope using a rheometer working in the viscosity mode. The temperature dependence of η0 conformed to the Arrhenius-Frenkel-Eyring equation. ΔGv decreased marginally with OXA concentration, and the least value was observed at an OXA concentration of 0.63 % by weight. Shear thinning behaviour was observed under higher shear rates for the terpolymer solutions in the presence and absence of OXA. The pseudoplasticity index (n) showed an abrupt initial increase on addition of OXA. The OXA concentration of 0.63 % by weight was advantageous for decreasing the viscosity of the polymer dope. The reduction in viscosity is attributed to the disturbed polymer-polymer interactions by way of H-bonding of OXA with the polymer. OXA-containing dope at higher shear rate could achieve very low viscosities. Copyright © 2004 Society of Chemical Industry
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