The kinetics of the anionic ring-opening polymerization of hexamethylcyclosiloxanes (D3) initiated by hexaphenylcyclotrisilazane trilithium(P3NLi)

in the presence of DMSO or THF as a promoter was studied.The conversion of D3 at different reaction time was determined from the ratio of the peak area of the NMR spectrum of D3 to that of the polymer.The reaction orders for THF

DMSO

D3 and P3NLi were calculated.The polymerization is a reaction of 1st order with respect to D3

THF and P3NLi

and 2nd order with respect to DMSO.The kinetic equations of the polymerization reactions were also proposed.The kinetics of THF and DMSO is vp=-d［D3］/dt=k［I］［D3］［THF］ and vp=-d［D3］/dt=k［I］［D3］［DMSO］2

respectively.The accelerating effect of DMSO was stronger than that of THF

and the rate constant of polymerization with DMSO as promoter was nearly 100 times as high as that of THF.