INITIATING SYSTEM ME3SICL ALCL3 FOR CATIONIC POLYMERIZATION OF 1,3-PENTADIENE IN TOLUENE/

Cat:ionic polymerization of 1,3-pentadiene (PD) initiated by trimethyl silyl chloride/aluminium chloride (TMSCl/AlCl3) was carried out in tol uene at 30 degrees C. The polymer yield was increased by the addition of TMSCl. However, introduction of TMSCl gave rise to a drop of the po lymer molecular weight. Kinetic results demonstrated that the polymeri zation initiated by TMSCl/AlCl3 was 2.8 times faster than that induced by AlCl3 alone. Various ethers and ketones were used to mediate the i nitiating system TMSCl/AlCl3. The polymer yield and molecular weight o f the polymer were decreased in the presence of ether. Ketones and eth ers had different effects on the polymerization, and the polymer yield and molecular weight were lower than those initiated by AlCl3 alone o r TMSCl/AlCl3. Structural evidence revealed that the polymerization wa s indeed initiated by AlCl3 and HCl resulting from hydrolysis of TMSCl by adventitious water.