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- Title
IPN hydrogels based on PNIPAAm and PVA-Ma networks: characterization through measure of LCST, swelling ratio and mechanical properties.
- Authors
Wenceslau, Adriana Cristina; Rubira, Adley Forti; Muniz, Edvani Curti
- Abstract
IPN hydrogels based on chemically modified poly(vinyl alcohol) (or PVA-Ma), with different degrees of substitution (DS), and poly(N-isopropylacrylamide) (or PNIPAAm) were obtained and characterized through measures of LCST, swelling ratio and mechanical properties. Linear PVA-Ma with several DS were obtained through the chemical reaction of PVA with glycidyl methacrylate (GMA). The DS of various PVA-Ma were determined through 1H NMR spectroscopy. Two steps were used for preparation the PVA-Ma/PNIPAAm membrane hydrogels. In the first step the PVA-Ma hydrogels (using PVA-Ma with different DS) were prepared by reaction of double bonds on PVA-Ma, using the persulfate/TEMED system. Using a photoreaction pathway in the second step, PNIPAAm network was prepared within the parent PVA-Ma network at different PVA-Ma/NIPAAm ratios. The studies show that degree of swelling ratio (SR) of PVA-Ma/PNIPAAm IPN hydrogels is dependent of temperature. The LCST for each IPN-hydrogel was determined by measuring the intensity of light transmitted through the hydrogel. The LCST of the IPN hydrogels ranged from 34.6 to 38.1°C. The elastic modules of swollen IPN hydrogels increased from 25 to 35°C but decreased by further warming to 45°C. The LCST, swelling ratio and mechanical properties of PVA-Ma/PNIPAAm IPN hydrogels can be tailored by tuning the PVAMa/ NIPAAm ratio.
- Subjects
CHEMICAL reactions; CHEMICAL processes; MECHANICAL behavior of materials; HYDROGELS; POLYVINYL alcohol
- Publication
Acta Scientiarum: Technology, 2012, Vol 34, Issue 2, p233
- ISSN
1806-2563
- Publication type
Article
- DOI
10.4025/actascitechnol.v34i2.15019