Abstract:

In this paper, thermo-sensitive poly （N-isopropylacrylamide） （PNIPAAm） hydrogels were first synthe-sized in the presence of microwave irradiation. The structure of the product and its effect on the swelling properties were next investigated. Then, the morphologies of the hydrogels in swollen and dry conditions were respectively characterized using SEM. Finally, the swelling properties and the corresponding kinetics of the hydrogels were revealed. The results show that, as compared with the hydrogels produced by means of water-bath heating, the hydrogels produced by microwave irradiation possess more and larger pores, which may result in higher swelling ratio below the lower critical solution temperature （LCST, tc） , lower swelling ratio above the LCST, faster swelling and all-swelling rates.

Key words: poly（N-isopropylacrylamide）, thermo-sensitive hydrogel, swelling radio, microwave irradiation, swelling kinetics