Structure and properties of cellulose/poly(N-isopropylacrylamide) hydrogels prepared by SIPN strategy.

Semi-interpenetrating polymer network (SIPN) strategy was employed to fabricate a kind of novel hydrogels composed of cellulose and poly(N-isopropylacrylamide) (PNIPAAm) in the presence of N,N'-methylenebisacrylamide (MBAAm) as the crosslinker and benzoyl peroxide (BPO) as the initiator. The results from FTIR and TGA indicated that the network indeed existed in the SIPN hydrogels. The data from experiments, those related to the swelling behavior of the hydrogels at different temperatures in particular, demonstrated the thermal sensitivity of these hydrogels. The impact of crosslinker content on the hydrogel properties was discussed as well. The swelling ratio of hydrogels decreased with increasing the content of MBAAm. Besides, the loading and releasing behavior of the hydrogels were examined using dimethyl methylene blue as a model drug. These novel hydrogels combining the advantages of natural polymer with thermal responsive behavior are of great potential to be applied to drug delivery and control release systems.