CATIONIC POLYMERIZATION OF 1,3-PENTADIENE WITH (CH3)(3)SICL ALCL(3)/

Cationic polymerizations of 1,3-pentadiene (PD) with AlCl3 in n-hexane was carried out in the absence and presence of trimethylsilyl chlorid e (TMSCl). The polymer yield is greatly increased by the addition of T MSCl, indicating that the TMSCl/AICl(3) combination is an efficient in itiating system for PD cationic polymerization. The polymerization rat e induced by TMSCl/AlCl3 is 10 times greater than that by AlCl3 alone. The introduction of TMSCl does not exert an effect on the crosslinkin g. reaction. The molecular weight of the polymer decreases with the ad dition of TMSCl to a extent and then remains constant. Structural evid ences demonstrate that the polymerization is indeed initiated by AlCl3 in combination with HCl resulting from hydrolysis of TMSCl by adventi tious water.