POLYMERIZATION OF O-TRIMETHYLSILYLPHENYLACETYLENE INITIATED BY A TUNGSTEN CARBENE COMPLEX

The polymerization of o-trimethylsilylphenylacetylene (o-Me(3)SiPA) in itiated by tungsten carbene complex (I) was investigated under various conditions. Both a larger molar mass and larger yield of polymer were obtained in CCl4 and CHCl3 and in the presence of a Lewis acid such a s AlCl3. The higher the temperature and the lower the initiator concen tration, the larger was the molar mass of the polymer. The molar mass increases with concentration of cocatalyst SnCl4 and shows a maximum v alue for a ratio [SnCl4]/[I]=1. Moreover, when a solution of tungsten carbene complex in CCl4 was irradiated with UV light, the molar mass w as remarkably enhanced. Kinetic orders and apparent rate constants wer e determined by gas chromatography. According to thermogravimetric res ults for poly(o-Me(3)SiPA), there is no significant interaction betwee n the polymer and oxygen below 260 degrees C. Above 260 degrees C, the loss of mass in the presence of oxygen follows a two-step process. X- Ray diffraction measurements show that poly(o-Me(3)SiPA) has an amorph ous structure.