Effects of chain structures of corn starches on starch‐based superabsorbent polymers

Abstract

Biodegradable superabsorbent polymers (SAPs) were synthesized in this study by graft copolymerization of monomers (acrylic acid or acrylamide) onto amylose and amylopectin, respectively, using potassium persulfate as an initiator and N,N 0 -methylenebisacrylamide as a cross-linker. The main purpose of this study is to investigate the effects of the chain structures of corn starches on the grafting ratio (GR) and physicochemical properties of starch-based SAPs including starch-graft-polyacrylic acid and starch-graft-polyacrylamide SAPs. The structure of these SAPs was characterized by FTIR, 13 C nuclear magnetic resonance ( 13 C-NMR), and thermogravimetric analysis (TGA), and the GR was evaluated by acid hydrolysis. We also investigated their swelling kinetics and reswelling capacity. The results show that the water absorption capacity and GR of amylose graft copolymers are superior to those of amylopectin graft copolymers; this may be due to the differences in structures and physicochemical properties between amylose and amylopectin.

Influence of Chain Structures of Starch on Water Absorption and Copper Binding of Starch‐Graft‐Itaconic Acid Hydrogels

“…Zou et al found that under the same reaction conditions, increasing the content of amylose in corn starch led to an increase in grafting ratio and grafting efficiency, which in turn led to an increase in water absorption. These results were in agreement with those obtained by Zhang et al, who found that pure amylose produces hydrogels with higher grafting ratio and swelling capacity than pure amylopectin. They attributed these results to the high molecular weight and branched structure of amylopectin, which caused an increase in viscosity and a decrease in mobility of the polymeric chains.…”

One‐step synthesis of corn starch urea based acrylate superabsorbents

“…The FTIR spectra are given in Figure . It can be seen that the spectrum of the original St exhibited a pattern similar to that in previously reported results . The typical IR spectra of St and PAA were observed, and the attribution of the primarily absorption peaks has been discussed in detail in previous literature, and some of the characteristic absorption peaks are also presented in Figure .…”

“…The grafting ratio and water absorption increased with decreasing amylose content, and this is different from the results of Zou et al . and Zhang et al . Incomplete gelatinized St aggregates increased with increasing amylose content on surfaces and cross sections of the copolymer…”

“…Different sources of St have been used as the grafting skeleton, coming from corn, wheat, potato, sweet potato, cassava, sago, amaranthus, and other crops . Most native, granular Stes consist of amylose with a linear structure and amylopectin with a branched structure.…”

Eco‐Friendly Synthesis of Hydrogels from Starch, Citric Acid, and Itaconic Acid: Swelling Capacity and Metal Chelation Properties

“…Starch has also been used for the production of superabsorbent hydrogels, in particular through the grafting of vinyl monomers . While this allows hydrogels to remain biodegradable, it does have drawbacks as well.…”