Preparation And Properties Of Semi-IPN Hydrogel Based On Poly(N, N-diethylacrylamide) With Response To Temperature And PH

In this thesis, three different kinds of hydrogels, P(2-dimethylamino ethyl methacrylate)/ P(N,N-diethylacrylamide) (PDMAEMA/PDEA) semi-IPN hydrogels, poly(N,N-diethylacrylami-de-co-itaconic acid)(P(DEA-co-IA)) hydrogels and poly(vinyl alcohol)/P(N,N-diethylacrylamide) (PVA/P(DEA-co-IA)) semi-IPN hydrogels were prepared by using free radical solution polymerization and semi-interpenetrating polymerization. The effects of the feed components, temperature and pH on the swelling behavior of the hydrogels were studied, and the rapid response properties of the hydrogels were investigated in detail, and the results are summarized as following:1. A novel semi-IPN hydrogel of PDMAEMA/PDEA was prepared at room temperature. Owing to the introduction of PDMAEMA component, the interconnected porous structure is generated. The temperature response rates of the semi-IPN hydrogels can be changed by modifying the proportion of PDMAEMA to DEA. The oscillating swelling/deswelling behavior of the semi-IPN hydrogels upon temperature changes around LCST depends on the PDMAEMA content. In addition, due to the existence of tertiary amino groups in the chains of PDMAEMA, the semi-IPN hydrogels also possess pH-sensitivity. Compared to PDEA hydrogels, semi-IPN hydrogels show a slower drug release rate, and the drug release rate reduces with increasing temperature, which is expected to obtain hydrogels with improved properties for potential applications in drug controlled system.2. P(DEA-co-IA) hydrogels were synthesized by changing the initial molar ratio of DEA to IA, N,N'-methylenebisacrylamide and total monomer concentration. From FTIR spectra, it can be concluded that the P(DEA-co-IA) hydrogels were successfully prepared. The interior morphology of the hydrogels illustrates the dependence of the morphology on the hydrogel compositions. In comparison with the PDEA hydrogels, the equilibrium swelling ratio (ESR) and lower critical solution temperature (LCST) of the P(DEA-co-IA) hydrogels increase with the increase of IA content in the feed. The swelling dynamics of the semi-IPN hydrogels was analyzed by Peppa's potential equation. The results show that the swelling mechanism would be transformed from Fickian diffusion to non-Fickian transport. In addition, the release behaviors of the model drug, aminophylline, were found to be dependent on hydrogel composition and environmental temperature.3. A series of PVA/P(DEA-co-IA) porous hydrogels with different pore sizes were prepared by semi-interpenetrating polymerization at room temperature. The semi-IPN hydrogels exhibite improved thermosensitive characteristics, such as faster deswelling and lower swelling rates and great oscillating deswelling-swelling behavior, and the level of improvement depends on the PVA content. The swelling dynamic transport of the hydrogels was analyzed based on the Fickian equation. The results show that the swelling mechanism would be transformed from Fickian diffusion to non-Fickian transport. In addition, the release behaviors of the model drug, aminophylline, were found to be dependent on hydrogel composition and environmental temperature.