Polymerization of octamethylcyclotetrasiloxane with hexamethyldisilazyl-lithium as initiator

This work focused on the anionic polymerization of octamethylcyclotetrasilo xane (D-4, D = Me2SiO2/2) initiated by a new kind of initiator hexamethydis ilazyl-lithium (MMNLi). Si-29-NMR spectroscopy and gas chromatography (GC) were used to characterize the polymerization products. The process was acce lerated by adding a small amount of high activity monomer D-3 and by raisin g the polymerization temperature. At the end of polymerization more than 95 % of the monomer was converted to polymer and only a very small amount of D -4 and D-5 remained in the polymers.