Rheological and thermal properties of saponified cassava starch- g-poly(acrylamide) superabsorbent polymers varying in grafting parameters and absorbency.

Parvathy, Prabha C.; Jyothi, Alummoottil. N.

ABSTRACT Cassava starch-graft-poly(acrylamide) superabsorbent polymers (SAPs) with varying absorbencies were synthesized. Weight average molecular weight ( Mw) of the hydrolyzed starch-graft-copolymers ranged from 1.6 × 106 to 2.8 × 106 g/mol, the largest being shown by the sample with highest percentage grafting. The storage ( G′) and loss modulus ( G″) of hydrogels were determined as a function of frequency. G″ was larger than G′ for the hydrogels with higher absorbencies and exhibited a liquid-like behavior. However, hydrogels with lower absorbencies showed a reverse viscoelastic behavior. The viscosity of hydrogels determined using a Brookfield viscometer at different shear rates was found to be larger for the hydrogels with higher absorbencies. The melting temperature ( Tm) and enthalpy change of fusion (Δ Hf) of the SAPs ranged from 149.7 to 177.7°C and 65 to 494.9 J/g, respectively and showed a positive correlation with grafting parameters and Mw. Heavy metal ion removal capacity of hydrogel followed the order Cu2 > Pb2 > Zn2 . © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40368.

CASSAVA starch; POLYACRYLAMIDE; SUPERABSORBENT polymers; GRAFTING (Horticulture); MOLECULAR weights

Journal of Applied Polymer Science, 2014, Vol 131, Issue 11, pn/a

0021-8995

Academic Journal

10.1002/app.40368