Polymer and Materials Science
Wiley InterScience Backfile Collection 1832-2000
Chemistry and Pharmacology
Methacrylic anhydride was polymerized, in high yields, at temperatures ranging from 1 to 80°, in benzene solution, to linear, soluble polymers. The polymethacrylic anhydride so prepared was hydrolyzed to the corresponding polymethacrylic acid and this poly(acid) esterified by reaction with diazomethane to yield polymethyl methacrylate. The result is given of an x-ray diffraction study of an unstretched film of polymethyl methacrylate prepared in a similar manner. The determination of the fraction of the polymer present in each of the three possible stereoconfigurations, isotactic, syndiotactic, and heterotactic, was made from a nuclear magnetic resonance investigation of the derived polymethyl methacrylate. The results indicate that the stereoconfiguration is influenced by the cyclic polymerization mechanism. The results also indicate that there is a bias toward increasing isotactic character in the polymers with an increase in polymerization temperature. Two possible explanations are offered: one in terms of a kinetic control of the steric placements and the other in terms of a balance between equilibrium and kinetic considerations.
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