Starch Grafted with Polyacrylic Acid as a Renewable Alternative for Fossil-Based Performance Polymers

Abstract

Graft copolymerization of acrylic acid onto starch can provide renewable alternatives for current applications of water-soluble performance polymers from fossil resources. In our laboratory, Fenton’s reagent was mostly used as the initiator for graft copolymerization experiments, in aqueous solutions. A major challenge with the homogeneous system is the selectivity of grafting versus homopolymer formation. Important factors that determine the grafting selectivity are discussed, and methods to improve it are proposed. In a batch process, adding monomer in portions over time proved successful. This provides a principal breakthrough of the trade-off between grafting percentage and graft selectivity that is characteristic for grafting with hydrophilic monomers.

Keywords

• starch graft copolymerization
• selectivity of the grafting reaction
• water solubility of the monomer as a key factor
• methods to improve selectivity with water-soluble monomers and indirect initiation