(1) Department of Polymer Science and Engineering, Chemistry Building, Nanjing University, Nanjing 210093, PRC;(2) The State Key Laboratory of Polymer Physics and Chemistry at Changchun, Changchun 130022, PRC
Abstract:
Glass transition for atactic poly(methyl methacrylate)(a-PMMA) prepared innano-cells by microemulsion polymerization was measured at afaster heating rate after slow cooling of the sample from atemperature above Tg. Anadditional enthalpy relaxation and glass transition wereobserved at higher temperatures for the a-PMMA sample due to the partialorganization of the chain segments which occurred duringmicroemulsion polymerization. The re-precipitateda-PMMA did not show anyself-organization under the same thermal conditions, althoughthere are no changes in molecular weight or tacticity of thepolymer chains. A depletion-interaction phenomenon wasunderstood to provide entropic force for the self-organizationof polymer chains inside the walls of the microemulsion cells.
