Résumé

Microcalorimetry and cloud point extrapolation indicate a lower critical solution temperature of 216 °C for poly(N,N-dimethylacrylamide) (PDMA). This is the highest phase-transition temperature in the poly(N,N-dialkylacrylamide) series. Cloud points were recorded from electrolyte solutions made of Na3PO4, CaCO3, (NH4)2SO4 and KOH. These measurements were realized below and beyond the boiling point of water. The hydrolytic properties of PDMA in superheated water (200 °C) were examined and verified using 1H NMR analysis. The knowledge of the phase-transition temperature of pure PDMA is of interest, as it is often a constituent of smart copolymers, to adjust the responsiveness to a desired temperature threshold.

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