A pH-Sensitive Biopolymer-Based Superabsorbent Nanocomposite from Sodium Alginate and Attapulgite: Synthesis, Characterization, and Swelling Behaviors

Abstract

Graft copolymerization reaction among sodium alginate (NaAlg), sodium acrylate (NaA), and nanoscale attapulgite (APT) was performed to fabricate a novel pH-sensitive NaAlg-g-PNaA/APT superabsorbent nanocomposite. FTIR spectra proved NaA monomers were grafted onto NaAlg backbone and APT participated in polymerization. FESEM, TEM, and TGA analyses revealed the better dispersion of APT fibrils in the matrix and the improved thermal stability. The swelling capacity and rate of the superabsorbent was clearly enhanced after introducing APT. The external salts and surfactants showed greater influence on the swelling behaviors. The nanocomposite exhibited reversible On-Off pH-sensitivity between pHs 2.0 and 7.4, and the intriguing pH-triggered deswelling behavior in various polyvinylperrodone (PVP) solutions was observed.