| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 5185394 | Polymer | 2009 | 5 Pages |
Thermosensitive phase separation of aqueous solutions of the random copolymers of N-isopropylacrylamide (iPA) and N,N-diethylacrylamide (dEA) (PiPA-dEA) and of iPA and N-isopropylmethacrylamide(iPMA) (PiPA-iPMA) with different compositions has been investigated by using calorimetry, turbidimetry and infrared spectroscopy. Though the phase transition temperature (Tp) of PiPA-iPMA is a linear function of its composition, a deviation from additivity is observed for that of PiPA-dEA, that is, it has a minimum value at iPA/dEAÂ =Â 1 (mol/mol). IR spectrum at the amide II mode of the copolymer suggests that part of N-H groups of iPA units form a hydrogen bond with CO groups of dEA units at TÂ >Â Tp as well as with those of the iPA units. Effects of methanol on Tp of these copolymers have also been studied.
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