Tuning the molecular weight distributions of vinylketone-based polymers using RAFT photopolymerization and UV photodegradation

The choice of chain transfer agent in reversible addition/fragmentation chain transfer polymerization has proven to be instrumental in modulating the dispersity of a certain polyphenyl vinyl ketone (PVK). The monomer, PVK, which can self-initiate when exposed to blue light, was used to synthesize homopolymers, block copolymers by extending with a different monomer and gradient polymers. Regardless of the polymer architecture or degree of polymerization, a consistent trend in polymer dispersity was quantified, with higher loadings of the less active chain transfer agent xanthate leading to higher dispersities. The dispersity could be further modulated by photodegradation of vinyl ketone polymers under UV irradiation.