Equilibrium bulk polymerization of 1,3-dioxolan |
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Authors: | R Binet J Leonard |
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Affiliation: | Department of Chemistry, Université Laval, Quebec 10, Canada |
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Abstract: | Cationic bulk polymerization of 1,3-dioxolan has been carried out in sealed ampoules using a high vacuum technique. The polymerization is initiated with triethyl oxonium hexafluorophosphate and the equilibrium between monomer and active polymer is attained within a few hours. Specific volumes of pure monomer and polymer in solution of its own monomer have been measured. Equilibrium measurements have been performed in the 40° to 141·4°C temperature range and the ceiling temperature is estimated to be 144° ± 2°C. The effect of short polymer chains on the equilibrium is discussed briefly. Values of ΔGlc, the free energy of polymerization of one mole of pure liquid monomer to one base-mole of amorphous polymer, are computed making allowance for the non-ideal mixing. Respective values of ?17.5 ± 0.8 kJ/mol and ?47.9 ± 2.2JK?1mol?1 are deduced for the corresponding ΔHlc and ΔSlc. ΔGlc is also computed from published data on equilibrium polymerization of 1,3-dioxolan in various solvents and the combined results for both types of polymerization yield ΔHlc = ?16.7 ± 0.5kJ/mol and ΔSlc = ?45.8 ± 1.5JK?1mol?1 for the 20° to 140°C range. |
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