Microcalorimetric Study of the Temperature-Induced Phase Separation in Aqueous Solutions of Poly(2-isopropyl-2-oxazolines)

摘要: The effect of temperature on aqueous solutions poly(2-isopropyl-2-oxazoline) (PIPOZ) samples molecular weights ranging from 1900 to 5700 g mol-1 was monitored by turbidimetry, high-sensitivity microcalorimetry (HS DSC), and pressure perturbation calorimetry (PPC) 10 80 °C. polymers were soluble in cold water underwent phase separation at TCP ∼ 45−63 °C, depending their weight. transition endothermic, with an enthalpy change 0.36 ± 0.01 1.16 kcal mol-1. coefficient thermal expansion PIPOZ (αpol), determined PPC, a sharp increase the corresponding onset transition, reaching maximum value T TCP. Microcalorimetric measurements carried out D2O NaCl solutions. thermodynamic volumetric changes associated are compared those two relat...