Poly-vinyl alcohol (PVA) crosslinked by trisodium trimetaphosphate (STMP) and sodium hexametaphosphate (SHMP): Effect of molecular weight, pH and phosphorylating agent on length of spacing arms, crosslinking density and water interaction

Publication date: Available online 21 October 2019Source: Journal of Molecular StructureAuthor(s): Gemma Leone, Marco Consumi, Simone Pepi, Alessio Pardini, Claudia Bonechi, Gabriella Tamasi, Alessandro Donati, Claudio Rossi, Agnese MagnaniAbstractPoly-vinyl alcohol (PVA) with different molecular weight (27 kDa, 31 kDa, 61 kDa, 125 kDa and 195 kDa) were phosphorylated with trisodium trimetaphosphate (STMP) or sodium hexa-metaphosphate (SHMP) working at pH 10 or 12. Strong chemical hydrogels (G’>G”) were obtained starting from polymers with higher MW (61 kDa, 125 kDa and 195 kDa). Infrared Spectroscopy, UV Spectrophotometry and Rheological analyses indicated that crosslinking density is a function of a correct balance between deprotonation of polymeric chain, viscosity of the solution and length of the spacing arms. STMP and SHMP, as phosphorylating agent, behave differently changing pH and polymer MW. Crosslinked density was reflected in different capability to interact with water changing the ratio between freezable free water, freezable bound water and not freezable water.Graphical abstract
Source: Journal of Molecular Structure - Category: Molecular Biology Source Type: research