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Glass Transition Distribution in Miscible Polymer Blends : from Calorimetry to Rheology

Reference : Peiluo SHI, Régis SCHACH, Etienne MUNCH, Hélène MONTES, and François LEQUEUX, to appear in Macromolecules. DOI : 10.1021/ma400417f

At their glass transition, simple liquids and polymers exhibit a broad spectrum of relaxation -with a width of more than 4 decades in time. Blends of miscible polymers exhibit even broader relaxation spectrum. Here, we assume that a blend can be considered as an ensemble of domains of various local glass transition temperatures. Using calorimetric data, with or without aging, we probe the distribution of glass transition temperature (Tg) of miscible polymer blends of Polybutadiene (PB) and Styrene Butadiene Rubber (SBR). Using self-consistent averaging method inspired by the Olroyd-Palierne model, we predict quantitatively, with no adjustable parameter, the viscoelastic spectrum of our blends from the Tg distribution obtained by calorimetry. This quantitative prediction confirms thus the assumption that mechanically, a blend can be considered as an ensemble of domains each of which having a different glass transition temperature.