Triphenylbismuthoniumylide as initiator in polymerization of styrene

Kinetics of solution polymerization of styrene has been examined at 60 +/- 0.2 degreesC with triphenylbismuthonium 1.2,3,4-tetraphenylcyclopentadienyl ide as free radical initiator. The initiator exponent [I](0.5) and the mono mer exponent [M](1.2), calculated from the kinetic data indicate that the s ystem follows ideal radical kinetics. The overall activation energy and ave rage value of k(p)(2)/k(t), are 27 kJ mol(-1) and 0.4 1 mol(-1) s(-1). The two protons of methylene groups are magnetically equivalent and give one li ne in the NMR spectrum of polymer, indicating syndiotactic nature of polyme r styrene. The trapping of bismuth in polymer matrix is confirmed from the scanning electron microscopy and the presence of six hyperfine lines in ele ctron spin resonance proves that the initiation is brought about by phenyl radical.