8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

P8.48Thu 811:10-14:00Glass transition and concentration fluctuation in polymerblends: DSC and viscoelastic measurementsPeiluo Shi, 1 Francois Lequeux, 1 and Hélène Montes 11 ESPCI-ParisTech, 10 rue Vauquelin, 75231, PARIS Cedex 5, FranceAt their glass transition, simple liquids and polymers exhibit a large spectrum of relaxation - witha width of about 4 decades in time. Mixtures exhibit even larger relaxation spectrums. It has beensuggested that for simple liquids, the width of the spectrum originates in the fluctuation of density[Long]. For mixtures, it has also been suggested the width of the spectrum is widened because ofconcentration fluctuations [Lodge, Shenogin, Long and Souche]. However, there are only scarceexperimental results on glass transition of mixtures. Here we show that we are able to probe therelaxation spectrum of miscible polymer mixtures using special temperature histories. We alsofind that the spectrum obtained from calorimetry is in reasonable agreement with the one obtainedfrom rheological measurements. As a conclusion we suggest that calorimetric measurements afteraging sequences are good candidates to determine the relaxation spectrum of mixtures near theirglass transition. This work has been done in collaboration with Michelin.48