Stereocomplex formation between enantiomeric poly(α‐methyl‐α‐ethyl‐β‐propiolactones): Effect of molecular weight |
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Authors: | Carole Fraschini Anne Pennors Robert E. Prud'homme |
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Affiliation: | 1. Département de Chimie, Université de Montréal, C.P.6128, Succursale Centre‐Ville, Montréal, Québec, Canada H3C 3J7;2. Département de Chimie, Université Laval, Cité Universitaire, Québec, Canada G1K 7P4;3. Département de Chimie, Université de Montréal, C.P.6128, Succursale Centre‐Ville, Montréal, Québec, Canada H3C 3J7Département de Chimie, Université de Montréal, C.P.6128, Succursale Centre‐Ville, Montréal, Québec, Canada H3C 3J7 |
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Abstract: | Optically pure S(?) and R(+)‐poly(α‐methyl‐α‐ethyl‐β‐propiolactones) (PMEPLs) of controlled low molecular weights were synthesized by anionic polymerization of the corresponding optically active monomers, and characterized using gel permeation chromatography, Maldi‐TOF mass spectrometry, and NMR spectroscopy. Blends of PMEPLs of opposite configurations and different molecular weights were investigated. All blends lead to the formation of a stereocomplex and its crystallization prevails over a wide range of mixing ratios. The stereocomplex melts 30–40 °C above that of the corresponding pure polymers, depending on the molecular weight; pairs of polymers having similar molecular weights exhibit the highest melting temperatures and enthalpies of fusion. Finally, when the stereocomplex is dispersed in a PMEPL matrix, it acts as a very effective nucleation agent for the crystallization of the polymer in excess. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2380–2389, 2007 |
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Keywords: | differential scanning calorimetry MALDI NMR PMEPL poly(propiolactones) stereocomplex |
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