Studies on molecular weight distribution of carbon fiber polymer precursors synthesized using mixed solvents

Krishnan, GS and Burkanudeen, A and Murali, N and Phadnis, H (2012) Studies on molecular weight distribution of carbon fiber polymer precursors synthesized using mixed solvents. Chinese Journal of Polymer Science, 30 (5). pp. 664-673.

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Abstract

The molecular weight distributions were estimated for carbon fiber polymer precursors such as poly(acrylonitrileco-itaconic acid) synthesized by semi batch solution polymerization in mixed solvents media with the azonitrile compounds as initiator under the different ratios of solvent and non solvent from 0.75 to 2.5 in weight. The copolymer was characterized by using Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (1H-NMR) analyses. The molecular weight distributions were evaluated by Mv/Mn ratios estimated from viscosity and osmotic measurements, and Mw/Mn estimated from size exclusion chromatography. The molecular weight distributions of these polymers as determined from Mv/Mn and Mw/Mn are 2.9 to 3.2 and 2.0 to 2.5 respectively. The molecular distributions were close to a narrow distribution of 2.0 when the solvent/non-solvent ratio was varied between 1.4 and 2.0. Intrinsic viscosity [η] as a function of molecular weight of poly(acrylonitrile-co-itaconic acid) was evaluated by means of low angle laser light scattering with size exclusion chromatography (SEC-LALLS) and viscometry with SEC (SEC-VISCO). The relationship between [η] and Mw for poly(acrylonitrile-co-itaconic acid) in DMF at 50°C was [η] = 1.1 × 10−5 Mw 0.79, where [η] is obtained in dL/g.

Item Type:	Article
Additional Information:	Copyright to this article belongs to M/s. Chinese Chemical Society
Uncontrolled Keywords:	Molecular weight distribution;Size exclusion chromatography; Osmometry;Viscometry;Polyacrylonitrile copolymer
Subjects:	CHEMISTRY AND MATERIALS > Chemistry and Materials (General)
Depositing User:	Ms. Alphones Mary
Date Deposited:	29 Apr 2013 07:58
Last Modified:	29 Apr 2013 07:58
URI:	http://nal-ir.nal.res.in/id/eprint/11617

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