Ring-Opening polymerization of ε-caprolactone using novel tin(ll) alkoxide initiators

Abstract

Two novel tin(II) alkoxides, namely: tin(II) hexoxide, Sn (OC 6H13)2 and tin(II) octoxide, Sn(OC 8H&17)2, have been synthesized for use as coordination-insertion initiators in the bulk ring-opening polymerization of ε-caprolactone. The kinetics of the polymerization reactions were studied at 140 °C by dilatometry. It was found that both alkoxides were slow to dissolve in the ε-caprolactone monomer due to their molecular aggregation in the solid state. As a result, the slow solubilization of the initiators gave rise to deviations from the expected first-order kinetics. Instead, the kinetic results adhered more closely to zero-order kinetics with apparent zero-order rate constants k0 of 6.58 × 10-1 and 4.63 × 10-2 mol l-1 min-1 for the hexoxide and octoxide respectively. © 2008 Trans Tech Publications, Switzerland.