Metal-free anionic polymerization of methyl methacrylate in tetrahydrofuran using bis(triphenylphosphoranilydene)ammonium (PNP+) as counterion

2000

Bis(triphenylphosphoranilydene)ammonium (PNP + ) triphenylmethanide (Ph 3 C - ) is a new metal-free initiator for the living polymerization of methyl methacrylate (MMA). The kinetics of the polymerization strongly depend on the metal counterion the initiator precursor. When the initiator is made from the metathesis reaction of Ph 3 CK and PNPCl, the polymerization follows first-order kinetics up to 0°C with half-lives below 0.1 s. The propagation rate constants are much higher than those obtained with tetraphenylphosphonium (TPP + ) cations, indicating a smaller fraction of dormant ylides. When the initiator is synthesized from Ph 3 CLi, polymerization proceeds much slower and molecular wei…