Natural superabsorbent plastic materials based on a functionalizedsoy protein

Abstract

A natural superabsorbent polymer (SAP) material based on an acylated soy protein was studied as a green alternative to non-biodegradable SAP. In order to obtain the natural SAPs, different amounts of succinic anhydride were used as acylating agent. Once the functionalized protein was obtained, it was mixed thoroughly with glycerol and then molded through a lab-scale injection molding device. Water uptake of samples obtained reached values much higher than those based on unacylated protein. Moreover, a greater extent of the acylation reaction led to higher water uptake values for the corre sponding SAPs, probably related to their higher hydrophilic character. Water imbibing capacity mea surements and thermogravimetrical analysis (TGA) seemed to confirm this. The presence of larger porous regions in acylated samples observed in SEM images could also play a role in their higher water uptake values. Furthermore, an increase in the extent of acylation reaction led to plastics with lower Young's modulus and higher extensibility.