Cationic polymerization of 1

3 pentadiene (PD) by trimethylsilyl trifluoromethanesulfonate ((CH3)3SiOSO2CF3) in combination with SbCl3 were carried out in n hexance at 30℃. Addition of SbCl3 into the (CH3)3SiOSO2CF3 induced PD polymerization. The polymer yield increases from 55% to 80%

the polymerization is accelerated 24 times and the molecular weight of polymer is 17 times. Various ketones were used to mediate the initiating system (CH3)3SiOSO2CF3/SbCl3

the more bulky the ketone is

the higher yield and molecular weight are obtained.The 1H-NMR and the IR show that the polymerization of PD was initiated by the SbCl3 in complexation with trific acid (HOTf) resulting from hydrolysis of (CH3)3 SiOSO2CF3 adventitious water.