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

• Published in: Journal of applied polymer science Vol. 131; no. 11; pp. np - n/a
• Main Authors: Parvathy, Prabha C., Jyothi, Alummoottil. N.
• Format: Journal Article
• Language: English
• Published: Hoboken, NJ Blackwell Publishing Ltd 05.06.2014; Wiley; Wiley Subscription Services, Inc
• Subjects: Applied sciences; biomaterials; biopolymers & renewable polymers; Cassava; copolymers; differential scanning calorimetry (DSC); Exact sciences and technology; glass transition; Grafting; Hydrogels; Loss modulus; Materials science; Melting; Molecular weight; Natural polymers; Organic polymers; Physicochemistry of polymers; Polymers; Properties and characterization; Shear rate; Solution and gel properties; Starch and polysaccharides; Superabsorbent polymers; New York; United States > US; Copper II; Viscosity; Viscoelasticity; copolymers; differential scanning calorimetry (DSC); Absorbent material; Graft copolymer; Property composition relationship; Metal ion; Starch graft copolymer; Absorptivity; Sodium acrylate copolymer; Grafting; Saponification; Thermal properties; Chemical modification; Acrylamide polymer; Oside polymer; Hydrogel; biomaterials; glass transition; biopolymers & renewable polymers; Rheological properties
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.40368

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 (ΔHf) 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.