Water absorption, retention and the swelling characteristics of cassava starch grafted with polyacrylic acid

J R Witono; I W Noordergraaf; H J Heeres; L P B M Janssen

doi:10.1016/j.carbpol.2013.12.056

Water absorption, retention and the swelling characteristics of cassava starch grafted with polyacrylic acid

Carbohydr Polym. 2014 Mar 15:103:325-32. doi: 10.1016/j.carbpol.2013.12.056. Epub 2013 Dec 22.

Authors

J R Witono¹, I W Noordergraaf², H J Heeres³, L P B M Janssen³

Affiliations

¹ Chemical Engineering Department, Parahyangan Catholic University, Bandung, Indonesia.
² Chemical Engineering Department, Groningen University, The Netherlands. Electronic address: i.w.noordergraaf@rug.nl.
³ Chemical Engineering Department, Groningen University, The Netherlands.

PMID: 24528736
DOI: 10.1016/j.carbpol.2013.12.056

Abstract

An important application of starch grafted with copolymers from unsaturated organic acids is the use as water absorbent. Although much research has been published in recent years, the kinetics of water absorption and the swelling behavior of starch based superabsorbents are relatively unexplored. Also, water retention under mechanical strain is usually not reported. Cassava starch was used since it has considerable economic potential in Asia. The gelatinized starch was grafted with acrylic acid and Fenton's initiator and crosslinked with N,N'-methylenebisacrylamide (MBAM). Besides a good initial absorption capacity, the product could retain up to 63 g H2O/g under severe suction. The material thus combines a good absorption capacity with sufficient gel strength. The mathematical analysis of the absorption kinetics shows that at conditions of practical interest, the rate of water penetration into the gel is determined by polymer chain relaxations and not by osmotic driven diffusion.

Keywords: (Water) Absorption kinetics; Acrylic acid; Cassava starch; Grafting; Superabsorbent; Water retention under force.