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

Poly-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...