Dynamic and equilibrium swelling of biodegradable starch-based superabsorbent polymers

Abstract

A series of biodegradable superabsorbent polymers (SAP's) based on starch grafted with acrylic acid (AA) and crosslinked with N,N'-methylenebisacrylamide (MBIS) were obtained. The parameters that define SAP's properties, such as starch type, amount of initiator, acrylic acid and crosslinker concentrations, and degree of neutralization were varied. The dynamic swelling was interpreted in terms of both a simple power of time equation and a more detailed model based on a coupled diffusion-relaxation mechanism. The diffusivity coefficients calculated from diffusion-relaxation model were compared with the microimages obtained by optical microscopic