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The Journal of the Royal Institute of Thailand Vol. 30 No. 3 Jul.-Sep. 2005 874 º≈¢Õß°√¥¡“‡≈Õ‘ °µà Õ°“√‡°‘ ¥ªØ‘ °‘ √‘ ¬“æÕ≈‘ ‡¡Õ‰√‡´™— π ¢ÕßÕ–§√‘ ≈“‰¡¥å /°√¥¡“‡≈Õ‘ °·≈–§à “°“√¥Ÿ ¥´÷ ¡πÈ ” Abstract Effects of Maleic Acid on Acrylamide/Maleic Acid Polymerization and Water Absorption Paweena Lertchanyakul 1 Somsak Damronglerd 1 Fellow of the Academy of Science, The Royal Institute, Thailand Suda Kiatkamjornwong 2 * Associate Fellow of the Academy of Science, The Royal Institute, Thailand Poly[acrylamide/maleic acid] hydrogels were synthesized by free radical polymerization, initiated by a redox initiator of ammoniumpersulfate (APS) and N,N,N’,N’ - tetramethylethylenediamine (TEMED). The crosslinking agent N,N’-methylenebisacrylamide (MBA) and N 2 flow rate, were used in the copolymerization. The copolymerization was carried out at 250 rpm, 45 o C under nitrogen atmosphere for 30 minutes. The synthesized polymers were dewatered by precipitation with excess methanol and drying at 60 o C in a vacuum oven for 24 hours. Various important parameters of maleic acid content, initiator content, co-initiator content, crosslinking agent content, N 2 flow rate and polymer- ization time in the polymerization were studied. The water absorbencies of the synthesized polymers in distilled water were investigated. The synthesized polymers were tested on swelling and adsorption of a water-soluble cationic dye of CI BB 41 (11154). The kinetic of water diffusion of the synthesized polymers was investigated. The synthesized polymers were characterized by Fourier Transform Infrared Spectrophotometry and Scanning Electron Microscopy. The effects of the influential reaction parameters on water absorbency of the synthesized polymers were investigated from which they were produced from the following recipe: molar ratio of acrylamide: maleic acid, 92 : 8; MBA 1% by weight of the monomers; APS 1% by weight of the monomers and TEMED 10% by weight of the monomers. The highest water absorbency of the synthesized polymer was 310 + 10 times its dry weight. The water absorbencies and dye adsorptions of the synthesized polymers increased with increasing maleic acid content. A kinetic study of the water absorption determining the transport mechanism was as a whole as the non-Fiction type diffusion. Key words : hydrogel, poly[acrylamide/maleic acid], dyestuff 1 Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand. 2 Multidisciplinary Program of Petrochemistry and Polymer Science, Department of Photographic Science and Printing Technology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand. * Corresponding author; e-mail: ksuda@chula.ac.th Phone: 0-2218-5347; fax: 0-2218-5041