Preparation and characterization of macroporous poly [2-(diethylamino)ethylmethacrylate-co-N,N-dimethylacrylamide] hydrogels by two step polymerization method

vPREPARATION AND CHARACTERIZATION OF MACROPOROUS POLY[2-(DIETHYLAMINO)ETHYLMETHACRYLATE-CO-N,N-DIMETHYLACRYLAMIDE) HYDROGELS BY TWO STEPPOLYMERIZATION METHOD(M.Sc. Thesis)Sıla KÜÇÜKTEPEGAZI UNIVERSITYINSTITUTE OF SCIENCE AND TECHNOLOGYJanuary 2006ABSTRACTTemperature sensitive poly[2-(diethylamino)ethylmethacrylate-co-N,N-dimethylacrylamide], P(DEEMA-co-DMAm), hydrogels have beensynthesized via three different chemical method by free-radicalcrosslinking copolymerization of 2-(diethylamino)ethylmethacrylate(DEEMA) and N,N-dimethylacrylamide (DMAm) in ethanol by using N,N?-methylene(bis)acrylamide (MBAAm) as crosslinker, ammoniumpersulfate (APS) as an initiator and N,N,N?,N?-tetramethylethylenediamine (TEMED) as an activator. In two stepprocedure, the initial polymerization was conducted for various timesat 180C, this step was being followed by polymerization for one fixedtime at -220C . These materials termed ?cryogels? were prepared by twostep polymerization. The second type of hydrogel was prepared viaconventional method (250C for 24h). Third type of hydrogel which arenon-ionic super porous hydrogels, was synthesized with the addition ofpore-forming agent(NaHCO3). The synthesized hydrogels werecharacterized with the detemination of the swelling ratio, dry geldensity and mesh size measurements. The average molecular massbetween crosslinks ( M c ), polymer-solvent interaction parameter ( χ )viand effective crosslinking density (ν eD ) were calculated from theequilibrium swelling ratio values. The swelling ratios of hydrogelsprepared by three different chemical method P(DEEMA-co-DMAm) wereexamined in pure water as a function of temperature. In addition, thedeswelling behaviour of P(DEEMA-ko-DMAm) was observed in purewater at 50 0C. It was designated that when the content of hydrophobiccomponent (DEEMA) in hydrogel increased, deswelling ratio alsoincreased. On the other hand, porous structure of thermally sensitiveP(DEEMA-co-DMAm) hydrogels were also investigated by usingscanning electron microscopy.All results show that; super porous P(DEEMA-ko-DMAm) hydrogelshave higher swelling ratio, looser mesh size and lower dry gel density.Science Code : 201.1.117Key Words : Macroporous gels, Cryogels, Superporous gels,Network parameters.Page Number : 94Supervisor : Assoc. Doç. Dr. Tuncer ÇAYKARA