Surface-Initiated Hydrogen Atom Transfer Reversible Addition–Fragmentation Chain Transfer Polymerization from Isotactic Polypropylene

Functionalizing isotactic polypropylene (iPP) surfaces with polymer brushes is of interest for biomedical materials, automotive parts, filtration, and packaging applications. Existing methods to graft from iPP require multiple synthetic steps or harsh stimuli such as γ-rays to initiate polymerization. Here, we describe surface-initiated hydrogen atom transfer reversible addition–fragmentation chain transfer polymerization (SI HAT-RAFT) from iPP to initiate controlled polymerization directly from the C–H bonds of iPP using visible light as a stimulus. Using a thioxanthone-derived photocatalyst and bis(trithiocarbonate) disulfide species for catalyst turnover, we achieve thick polymer brushes using a variety of acrylic monomers. Furthermore, we grafted from commercial iPP samples, including food packaging and surgical mesh. Finally, we demonstrate improved surface properties of iPP by testing the adhesion of grafted polymer surfaces to paint and aluminum. We expect this method will be an enabling technology for preparing a wide range of iPP materials.