Dresden 2003 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 1: Polymerschmelzen

CPP 1.12: Vortrag

Montag, 24. März 2003, 12:45–13:00, ZEU/160

Similarities between phase separatin of polymer blends and reaction-induced phase separation — •Ingo Alig, Marco Holst , and Maximilian Rüllmann — Deutsches Kunststoff-Institut,Schlossgartenstr.6, D-64289 Darmstadt

Small-angle light scattering (SALS) and time resolved microscopy have been performed to study the phase separation kinetics in binary polymer mixtures (PEMS/PDMS) and phase separating reaction mixtures (epoxy/polysulfone) during continuous quenches (temperature ramps) and isothermal reaction, respectively.

For the critical PEMS/PDMS mixture it was found that the time evolution of the scattering curves in a continuous quenching experiment can be scaled by the cooling rate. Furthermore, a secondary phase separation was found and could be explained by the competition between interdiffusion and structure gowth. For off-critical mixtures nucleation and growth was observed.

The epoxy/polysulfone mixtures investigated during reaction-induced phase separation show similar features: coarsening and pinning of the structure growth and secondary phase separation.

We discuss the similarity between continuous quenching of chemically stable binary mixtures and the reaction-induced phase separation in a generalied phase diagram (product of Flory-Huggins parameter and degree of polymerization versus composition) by including gelation and vitrification into the diagram.