UV POLYMERIZATION OF POLY (N-ISOPROPYLACRYLAMIDE) HYDROGEL

UV POLIMERIZACIJA POLI (N-ISOPROPILAKRILAMIDNEGA) HIDROGELA

Manja Kurečič1,2, Majda Sfiligoj-Smole1,2, Karin Stana-Kleinschek1,2

1Center of excellence for polymer materials and technologies (PoliMaT), Tehnološki park 24, SI-1000 Ljubljana, Slovenia
2University of Maribor, Faculty of Mechanical Engineering, Laboratory for Characterization and Processing of Polymers, Smetanova 17, SI-2000 Maribor, Slovenia

[email protected]

Prejem rokopisa – received: 2011-09-30; sprejem za objavo – accepted for publication: 2011-11-07

This contribution is focused on the determination of polymerization and crosslinking mechanism of poly (N-isopropyl- acralymide) hydrogel and its swelling properties. Hydrogels were synthesized by environmental friendly UV polymerization method, from monomer N-isopropylacrylamide (NIPAM) and crosslinker N,N´-methylenebisacrylamide (BIS) of different concentrations. UV polymerization was performed in an UV chamber using UVA light with the wave length 350 nm. Surface morphology and pore structure analysis was carried out using SEM microscopy. The polymerization and crosslinking mechanism was determined by Fourier Transform Infrared spectroscopy (FT-IR). It was confirmed that crosslinker concentration influences the hydrogel structure and swelling properties. By increasing the crosllinker concentration the hydrogel structure changes from homogen to heterogen and the equilibrium degree of swelling decreases.

Keywords: poly (N-isopropylacrylamide) hydrogel, UV polymerization, FTIR, polymerization mechanism, swelling properties, SEM

V prispevku je predstavljen mehanizem polimerizacije in zamreženja poli(N-isopropilakrilamidnega) hidrogela in njegova sposobnost nabrekanja. Hidrogele smo sintetizirali z okolju prijazno metodo UV polimerizacije iz monomera N-isopropilakrilamida (NIPAM) in zamreževalca N,N´-metilenebisakrilamida (BIS) različnih koncentracij. UV polimerizacija je potekala v UV komori z UVA svetlobo valovne dolžine 350 nm. Površinsko morfologijo in strukturo por smo spremljali s SEM mikroskopijo. Mehanizem polimerizacije in zamreženja smo določili na podlagi posnetih spektrov s Fourier Transform Infrardečo spektroskopijo (FT-IR). Ugotovili smo, da koncentracija zamreževalca vpliva na strukturo hidrogela in njegovo sposobnost nabrekanja. Z večanjem koncentracije zamreževalca pride do spremembe v strukturi hidrogela iz homogene v heterogeno, kar vpliva na zmanjšanje sposobnosti nabrekanja.

Ključne besede: poli (N-isopropilakrilamide) hidrogel, UV polimerizacija, FTIR, mehanizem polimerizacije, nabrekanje, SEM