INTRINSIC NONSOLVENT POLYMERIZATION METHOD FOR SYNTHESIS OF POLYACETYLENE FILMS

We have developed a novel solvent-free polymerization method for synth esis of highly stretchable and highly conducting polyacetylene film. I n this procedure, we prepare a catalyst by mixing tetraalkoxytitanium, Ti(OR)4, with trialkylaluminum, AlR3, without solvent. The catalyst i s aged at room temperature for 1 hour followed by an aging at high tem perature of 150-degrees-C for 1 hour, and then, it is subjected to an acetylene polymerization at -78-degrees-C. Since the procedure is comp letely free from solvent until the end of polymerization, it can be ca lled an 'intrinsic non-solvent polymerization method. The method enabl es us to prepare an ultimately concentrated catalyst that is promising to synthesize polyacetylene films with high density and high stretcha bility. A preferable Al/Ti ratio is found to be 4 - 5, but not 2 that has been optimized for high-temperature aged catalysts. This result su ggests that the co-catalyst, AlR3, might play a role of solvent toward s catalytically active complexes formed Ti(OR)4 and AlR3.