In this paper, N-isopropylacrylamide (NIPA) was synthesized by acrylonitril
e and isopropanol. Poly(N-isopropylacrylamide) (PNIPA) was prepared by a ch
emical method. The dependence of its swelling behavior on temperature was s
tudied. Results showed that PNIPA hydrogel was a temperature-sensitive gel.
Its LCST (lower critical solution temperature) was about 32 degrees C, and
its swelling ratio (at 20 degrees C) was about 17-18.
Sodium acrylate (SA) and sodium methylacrylate (SMA) were copolymerized wit
h NIPA respectively. Equilibrium swelling ratios of the copolymer hydrogels
at lower temperature were two to three times that of PNIPA. The LCST of th
e copolymer hydrogels could be controlled between 32 and 45 degrees C by ad
justing the content of SA or SMA.
Kinetics of P(NIPA-co-SA) hydrogels, whether swelling or shrinking processe
s, were in good agreement with apparent second order kinetic equations.
Several experiments were designed to separate aqueous bovine serum albumin
solution using the hydrogels prepared above. The separation efficiency was
about 80%. Copyright (C) 2000 John Wiley & Sons, Ltd.