Journal
MACROMOLECULES
Volume 37, Issue 7, Pages 2556-2562Publisher
AMER CHEMICAL SOC
DOI: 10.1021/ma0358733
Keywords
-
Categories
Ask authors/readers for more resources
The effect of temperature on aqueous solutions of poly(2-isopropyl-2-oxazoline) (PIPOZ) samples of molecular weights ranging from 1900 to 5700 g mol(-1) was monitored by turbidimetry, high-sensitivity microcalorimetry (HS DSC), and pressure perturbation calorimetry (PPC) from 10 to 80 degreesC. The polymers were soluble in cold water and underwent phase separation at T-CP similar to 45-63 degreesC, depending on their molecular weight. The phase transition was endothermic, with an enthalpy change ranging from 0.36 +/- 0.01 to 1.16 +/- 0.01 kcal mol(-1). The coefficient of thermal expansion of PIPOZ in water (alpha(pol)), determined by PPC, underwent a sharp increase at the temperature corresponding to the onset of phase transition, reaching a maximum value at T similar to T-CP. Microcalorimetric measurements were carried out with solutions of PIPOZ samples in D2O and in aqueous NaCl solutions. The thermodynamic and volumetric changes associated with the phase transition of aqueous PIPOZ solutions are compared to those of aqueous solutions of two related polymers, poly(vinylcaprolactam) and poly(N-isopropylacrylamide) (PNIPAM), a polymer structurally related to PIPOZ that undergoes a phase transition in water at similar to31 degreesC.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available