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Synthesis and characterization of new pH- and thermo-responsive hydrogels based on N-isopropylacrylamide and 2-oxazolines / Síntesis y caracterización de nuevos hidrogeles sensibles al pH y la temperatura basados en N-isopropilacrilamida y 2-oxazolinas

New pH- and thermo-responsive hydrogels (HG) were synthesized by free radical polymerization of N-isopropylacrylamide and a macromonomer, which was a hydrolyzed random copolymer of 2-carboxyethyl- and 2-methyl-2-oxazoline, using a bisacrylamide as crosslinker. The polymerization was carried out in a mixture of water and ethanol at room temperature and was initiated by ammonium peroxodisulfate. The HG showed conformational transitions with variation of temperature and/or pH-value and as a function of hydrogel composition. This property was shown macroscopically as hydrogel contraction or expansion. The HG structures were characterized by high-resolution magic angle spinning (HRMAS) NMR spectroscopy. The thermal properties, in particular the lower critical solution temperatures, were determined by temperature-dependent HRMAS NMR measurements and differential scanning calorimetry. The pH responsibility was determined by swelling experiments in water at different pH values.

Identiferoai:union.ndltd.org:PUCP/oai:tesis.pucp.edu.pe:20.500.12404/22220
Date28 April 2022
CreatorsCampos Dávila, Estuardo Job
ContributorsRueda Sanchez, Juan Carlos
PublisherPontificia Universidad Católica del Perú, PE
Source SetsPontificia Universidad Católica del Perú
LanguageEnglish
Detected LanguageEnglish
Typeinfo:eu-repo/semantics/masterThesis
Formatapplication/pdf
Rightsinfo:eu-repo/semantics/openAccess, Atribución 2.5 Perú, http://creativecommons.org/licenses/by/2.5/pe/

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