A kinetic investigation of thermal degradation of poly(vinyl formals)

Chanda, Manas and Kumar, Jaywanth WS and Raghavendrachar, P (1979) A kinetic investigation of thermal degradation of poly(vinyl formals). In: Journal of Applied Polymer Science, 23 (3). pp. 755-764.

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Abstract

Several samples of poly(vinyl formal) having the same vinyl alcohol content (8–9%) but varying contents of vinyl acetate (6–22%) and vinyl formol (70–85%) were prepared and subjected to thermogravimetric analysis, in air and nitrogen atmospheres, employing both isothermal and dynamic methods. Kinetic parameters determined from both the isothermal and dynamic TGA data are compared. The activation energy is seen to be largely dependent on the degree of conversion, implying a complex degradation reaction. The activation energy is also much less for degradation in air than in nitrogen, which can be explained by a reaction with oxygen-producing structures favoring degradation. The activation energy is less sensitive to variation in polymer composition for degradation in air than in nitrogen. Thus, in the dynamic process, the activation energy value decreases (from 36 to 23 kcal/mole) with increasing acetate content (from 6 to 22%) in nitrogen atmosphere, while in air the activation energy value increases only moderately (from 21 to 27 kcal/mole) with increasing acetate content (from 6 to 22%). The order of reaction is nearly unity, irrespective of the composition of the polymer, both in air and nitrogen.

Item Type:	Journal Article
Publication:	Journal of Applied Polymer Science
Publisher:	John Wiley & Sons
Additional Information:	Copyright of this article belongs to John Wiley & Sons.
Department/Centre:	Division of Mechanical Sciences > Chemical Engineering
Date Deposited:	16 Dec 2010 07:53
Last Modified:	16 Dec 2010 07:53
URI:	http://eprints.iisc.ac.in/id/eprint/34359

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