Study On The Synthesis And Properties Of Ph/Temperature-responsive Poly(n-acryloyl Glycinates) Hydrogels

The environment-sensitive polymer hydrogels is a kind of intelligent material, its structure, physical and chemical properties can respond to small changes of the external environment conditions such as pH, temperature, ionic strength, electric field, magnetic field, light and so on. Among them, pH and temperature sensitive hydrogels have attracted much interest for their fundamental and application fields including drug delivery system, enzyme immobilization, biomaterials separation and purification, tissue engineering, biomimetic materials, chemical valves and so on.In this paper, we synthesized pH-temperature responsive poly(N-acryloyl glycinates) copolymer hydrogels, mainly discussed their temperature-pH sensitivity and application in drug release. In addition, differential scanning calorimetry (DSC) studies were also performed to determine the state of water in the swollen hydrogels.The thesis includes three sections, the main contents are listed as follow:Chapter I: The definition, classification, preparation, characterization methods of intelligent hydrogels have been presented in detail. At the same time, we introduced the advance in the synthesis of temperature-pH sensitive hydrogels and its application in biological engineering field and so on.Chapter II: Firstly, the copolymer hydrogel(PMEA) were prepared by free radical copolymerization in aqueous solution of NAGME, NAGEE and AAc, which was responsive in the physiological temperature range. The swelling characteristics of these hydrogels were systematically investigated as a function of pH and temperature and add inorganic salt ions. In addition, the caffeine as the model drug was loaded into copolymer hydrogels, the caffeine controlled-release from the pH-temperature copolymer hydrogel was also studied as functions of pH value, temperature by ultraviolet-visible spectrophotometer.Chapter III: The semi-interpenetrating polymer network (SIPN) hydrogels based on poly(N-acryloyl glycinates) and PEG has been prepared. The swelling behaviors of semi-IPN hydrogels in distilled water were studied with different PEG and crosslinker content. The effects of pH and add inorganic salt ions on the swelling behavior of hydrogel were systematically studied as well. In addition, the state of water in the semi-PN hydrogels was also investigated with differential scanning calorimetry(DSC).