Synthesis and characterization of PEPO grafted carboxymethyl guar and carboxymethyl tamarind as new thermo-associating polymers

• Published in: Carbohydrate polymers Vol. 117; pp. 331 - 338
• Main Authors: Gupta, Nivika R., Torris A. T, Arun, Wadgaonkar, Prakash P., Rajamohanan, P.R., Ducouret, Guylaine, Hourdet, Dominique, Creton, Costantino, Badiger, Manohar V.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 06.03.2015; Elsevier
• Subjects: Carboxymethyl guar; Carboxymethyl tamarind; Condensed Matter; Elasticity; Physics; Plant Gums - chemistry; Pluronics; Poloxamer - analogs & derivatives; Poloxamer - chemistry; Polymerization; Rheology; Soft Condensed Matter; Solution behavior; Thermo-associating polymers; Carboxymethyl tamarind; Solution behavior; Thermo-associating polymers; Pluronics; Carboxymethyl guar; Rheology
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2014.09.073

•New thermo-associating polymers based on carboxymethyl guar (CMG) and carboxymethyl tamarind (CMT) were synthesized using PEPO [Pluronics] as LCST chain.•Polymer solutions exhibited interesting thermo-responsive properties at moderate temperature.•Temperature of association, Tassoc was elegantly determined by 1H NMR line width transitions and rheological experiments.•The influence of salt and surfactants on Tassoc, indicated the “Salting out” and “Salting in” behavior, respectively.•These polymers are non-toxic, biodegradable and show promise as smart injectables in controlled release technology. New thermo associating polymers were designed and synthesized by grafting amino terminated poly(ethylene oxide-co-propylene oxide) (PEPO) onto carboxymethyl guar (CMG) and carboxymethyl tamarind (CMT). The grafting was performed by coupling reaction between NH2 groups of PEPO and COOH groups of CMG and CMT using water-soluble EDC/NHS as coupling agents. The grafting efficiency and the temperature of thermo-association, Tassoc in the copolymer were studied by NMR spectroscopy. The graft copolymers, CMG-g-PEPO and CMT-g-PEPO exhibited interesting thermo-associating behavior which was evidenced by the detailed rheological and fluorescence measurements. The visco-elastic properties (storage modulus, G’; loss modulus, G”) of the copolymer solutions were investigated using oscillatory shear experiments. The influence of salt and surfactant on the Tassoc was also studied by rheology, where the phenomenon of “Salting out” and “Salting in” was observed for salt and surfactant, respectively, which can give an easy access to tunable properties of these copolymers. These thermo-associating polymers with biodegradable nature of CMG and CMT can have potential applications as smart injectables in controlled release technology and as thickeners in cosmetics and pharmaceutical formulations.