Thermo-responsive microfibrillar graft copolymer based on carboxymethylagarose and N-isopropylacrylamide. (January 2020)

• Record Type: Journal Article
• Authors: Ortiz, J. Andrés; Catalina, Fernando; Corrales, Teresa; Soto, Camila; Zapata, Paula A.
• Is Part Of: Polymer testing. Volume 81(2020)
• Publication Date: 2020-01
• Subjects: Agarose -- NIPAAm -- Carboxymethylation -- Graft copolymerization -- Thermoresponsive materials; Polymers -- Testing -- Periodicals; Polymères -- Tests -- Périodiques; 620.1920287
• DOI: 10.1016/j.polymertesting.2019.106266
• Languages: English
• ISSNs: 0142-9418

Abstract

Abstract: Carboxymethylation of agarose with ClCH2 COOH in 2-propanol, formamide or dimethyl sulfoxide were evaluated in order to obtain water soluble derivatives. Higher yield (86%) and degree of substitution of carboxymethylation in primary alcoholic groups (0.70) were obtained using dimethyl sulfoxide. Carboxymethylagarose- g -PNIPAAm copolymers were synthesized by free radical graft copolymerization using Ce 4+ and S2 O8 2− /TEMED as initiators via conventional or microwave-assisted methods. Carboxymethyl derivatives and graft copolymers were characterized by FT-IR and NMR spectroscopies, elemental analysis, TGA and DSC and morphology analysis by SEM and AFM. High nitrogen content (9.7%) was found with Ce 4+ by conventional method and the obtained analysis allowed to confirm the NIPAAm grafting on the carboxymethylagarose chain. Thermoresponsive materials have a low critical solution temperature between 32 and 34 °C. Thermal stability increased ca. 60% with PNIPAAm grafting. Surface analysis of copolymers reveals a microfibrillar type morphology with diameter of 4–6 μm. Synthesized glycoconjugates could find applications in bioactive compounds transport in biological systems. Highlights: Graft copolymers of carboxymethylagarose (CMAGA) with NIPAAm were synthesized. High PNIPAAm grafting was obtained by free radical copolymerization with Ce 4+ . Thermoresponsive CMAGA- g -PNIPAAm copolymers showed a LCST range between 32 and 34 °C. Copolymers surface reveals a microfibrillar type morphology with diameter of 4–6 μm. Copolymers could find applications in bioactive transport in biological systems.