Synthesis And Properties Of PVP-PDMS Polymer Networks With An Amphiphilic Structure

Amphiphilic networks(APCNs) are a class of polymer network’system covalently linked by hydrophilic and hydrophobic chain segments, which leads to the formation of micro-phase separation structure. The hydrophilic and hydrophobic segments retain their physical and chemical properties respectively, which show unique properties of not only swelling in water but also swelling in organic solvents. APCNs show a wide range of potential applications in intelligent polymer materials, soft contact lenses, medical compatibility of materials and biomedical separation materials due to their unique performance.The hydrophilic and hydrophobic segments are thermodynamically incompatible, therefore, the difficulty to prepare APCNs lies in how to synthesize the two segments in APCNs. Here, a simple radical copolymerization route is utilized to prepare a new APCNs materials where polyvinylpyrrolidone(PVP) is used as the hydrophilic component and polydimethylsiloxane(PDMS) as the hydrophobic component. The different properties of the prepared APCNs are measured, i.e. its swelling ratio in water, optical properties and selective permeability of glucose, insulin and bovine serum albumin. The main contents are as following:l.The modifier 2-propenoic acid-3-(1,1,3,3-tetramethyldisiloxanyl) propyl ester (SiH-MA) is synthesized by hydrosilylation reaction using tetramethyldisiloxane (TMDSO) and allyl methacrylate(AMA). The preferable reaction condition to synthesize SiH-MA is the molar ratio of TMDSO to AMA is 1.1:1, the reaction temperature is 32℃, the reaction time is 3h, and Karstedt’s catalyst is 20ppm, the yield is 20%. Vinyl-terminated PDMS is modified by Si-MA through hydrosilylation reaction and the preferable reaction condition is the molar ratio of Vi-PDMS-Vi to SiH-MA is 1:1, toluene as solvent, the reaction temperature is 55℃, and the reaction time is 2h.2.The amphiphilic graft copolymers are synthesized by the radical copolymeri- zation of NVP with modified PDMS macromolecular chain, where AIBN is used as initiator. The different preparation conditions are investigated, i.e. the type of solvent, reaction temperature and etc. The products are characterized with IR and 1HNMR. Polymethylhydrosiloxane(PMHS) is used as the cross-linking agent to prepare APCNs through hydrosilylation reaction. The different conditions are studied, i.e. the content of cross-linking agent, catalyst concentration, monomer concentration, and initiator concentration. It is found that the soluble content Sol% is lower than 10%, the equilibrium water swelling Sw and the transmission rate of APCNs in both dry and swollen states increase with increasing PVP content. When PVP content reaches 70%, the transmittance of the water-swollen APCNs reaches a maximum; Sw gets a maximum when AIBN amount is 1.25%, the Sol% decreases with increasing amount of AIBN.3.The composite APCNs is prepared from the coating of APCNs on non-woven fabrics, and its permeability properties are measured, i.e. the permeability to glucose, inulin, bovine serum albumin(BSA). The influence of initiator concentration on permeability performance is investigated, via the permeability property of glucose and inulin determined by sulfuric acid-anthrone and the permeability of BSA tested by ultraviolet spectrophotometry. The experiment results show that the permeability rate of glucose and inulin increase with increasing amount of initiator AIBN, while BSA cannot pass through APCNs.