热敏材料聚N-异丙基丙烯酰胺的结构对其溶胀性能影响

本文主要研究热敏材料聚N-异丙基丙烯酰胺 (PNIPAAm) 的结构对其溶胀性能影响。分别采用水热法和微波辐射法合成PNIPAAm热敏水凝胶，应用扫描电镜观察了两种合成方法制得的水凝胶的表面结构，测定了水凝胶随温度变化的溶胀率曲线及其溶胀和退溶胀动力学，并讨论了水凝胶的结构对其溶胀率的影响。结果表明：与水浴法制备的水凝胶相比，微波辐射法所得到的水凝胶无论是在干燥状态下还是溶胀状态下都具有更为丰富发达且较大的孔隙结构，在溶胀过程中，微波辐射法合成的水凝胶在临界溶解温度(LCST)以下具更高的溶胀率，而在LCST以上时，能更多地释放水而具有更低的溶胀率。此外，微波辐射所合成的水凝胶由于具有较为发达的孔隙结构，使其比水浴法制备的水凝胶具有更快的溶胀速度和退溶胀速度。

Influence of the Structure of Thermo-sensitive PNIPAAm Hydrogels Synthesized by Microwave Irradiation on Their Swelling Properties

In this paper, the effects of textural properties of the poly (N-isopropylacrylamide) (PNIPAAm) hydrogels on their swelling properties were investigated. The PNIPAAm hydrogels were synthesized respectively by microwave irradiation method and water-bath heating method, and their morphologies in the dried and swollen states were characterized by Scanning Electron Microscope (SEM). The swelling curves with the change of the water temperature and their swelling and deswelling kinetics were measured. The effects of the textural properties of the PNIPAAm hydrogels were discussed. Results showed that the PNIPAAm hydrogels synthesized by microwave irradiation method had much more pores than that of the hydrogels synthesized by water-bath heating methods in both dried and swollen states. During the swelling process, the PNIPAAm hydrogels synthesized by microwave irradiation had much higher swelling ratios below LCST and could discharged much water with lower swelling ratios above LCST in comparison with that of the hydrogels synthesized by water-bath heating. Mealtimes, the PNIPAAm hydrogels synthesized by microwave irradiation had faster swelling and diswelling rates due to their developed porous structure.