Protein-Polymer Grafts via a Soy Protein Derived Macro-RAFT Chain Transfer Agent

Methodology to produce materials derived from renewable resources is of great importance in decreasing both environmental impact as well as dependence on fossil fuels. We report a straightforward method of polymer grafting to soy protein hydrolysates, which are available in surplus. Benzylthiocarbonate moieties were installed on the protein surface via amidation of free amino groups, creating a protein macro chain transfer agent (CTA) for reversible addition fragmentation transfer (RAFT) polymerization. We found that subjection of this soy protein macro-CTA (SP-CTA) to RAFT polymerization conditions with polar acrylate monomers resulted in protein-polymer nanometer-scale particles with solubility properties dictated by monomer polarity. Polymer grafting, particle size and polymerization were characterized by elemental analysis, transmission electron microscopy and gel permeation chromatography. We anticipate that this method of grafting will be of use in generation of new materials based on renewable resources.