ISSN:
0025-116X
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
The copolymerization of styrene (S) with maleic anhydride (MAn) in 1,4-dioxane at 60, 70 and 80°C up to high conversion (≈ 98%) was followed by differential scanning calorimetry. The rate of copolymerization increases up to 20 - 40% conversion of both monomers and then gradually decreases to zero. The increase in the copolymerization rate is more pronounced for equimolar ratios [S]/[MAn] as compared to ratios with an excess of S. For a given mole ratio of S and MAn the copolymerization rate in 1,4-dioxane is higher at higher total monomer concentrations and/or at higher temperatures. The heat of copolymerization is 81,6 kj · mol-1 for the equimolar [S]/[MAn] mixture. For mixtures with [S]/[MAn] 〉 1 the heat of reaction is between 70 and 80 kj · mol-1. The limitingconversion of styrene for [S]/[MAn] = 1 is about 98%, and for [S]/[MAn] 〉 1 it is a function of the [S]/[MAn] ratio. Assuming exclusively the formation of an alternating S/MAn copolymer the following relation is derived. \documentclass{article}\pagestyle{empty}\begin{document}$$\begin{array}{*{20}c} {\ln \left[ {\left( {\bar k_p /\bar k_t^{0,5} } \right)/\left( {{\rm dm}^{3/2} \cdot {\rm mol}^{ - 1/2} \cdot {\rm s}^{ - 1/2} } \right)} \right] = 2,478 - \frac{{8570}}{{{\rm RT}/\left( {{\rm J} \cdot {\rm mol}^{ - 1} } \right)}}} \hfill \\ {\left( {{\rm R} = 9,31441{\rm J} \cdot {\rm K}^{ - 1} \cdot {\rm mol}^{ - 1} } \right)} \hfill \\ \end{array}$$\end{document} for the ratio of the apparent rate constants of propagation k̄p, and termination k̄〈/t.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/macp.1983.021840620
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