SYNTHESIS AND ELECTRICAL CONDUCTIVITY MEASUREMENT OF POLYPHENYLACETYLENE AND ITS DERIVATIVES

Polyphenylacetylene and its derivatives were synthesized for the investigation of the effects on electrical conductivity caused by the highly conjugated systems and electron-withdrawing substituents on the conjugated side chain. The polymerization of phenylacetylene to polyphenylacetylene was undertaken by combined catalysts, triethyl aluminum and titanium tetraethoxide. The reaction conditions were investigated by gas chromatography at different temperatures (-80, 25, 140(DEGREES)C), in several solvents (benzene, chlorobenzene, toluene, cyclohexane, nitrobenzene) with different mole ratios of catalysts (Al/Ti: 1.5, 3.0, 4.5, 6.0, 9.0), at different aging times of catalysts (2 min., 10 min., 40 min), and by different addition orders. The derivatives of polyphenylacetylene were obtained by the acylation of polyphenylacetylene with p-nitrobenzoyl chloride, the sulfonation of polyphenylacetylene with benzenesulfonyl chloride, and the formation of polyphenylacetylene complex with complexing agents such as bromine, iodine, iodine chloride, boron trifluoride and ferric chloride. The propagating steps in the polymerization were suggested to involve a four-center mechanism. The electrical conductivity of polyphenylacetylene and its derivatives was measured by in-line four probe measurement. The results show these polymers have conductivities in the range of 10('-10) to 10('-3) ohm('-1) cm('-1.) This confirms that the highly conjugated system and electron-withdrawing substituents on the conjugated system and electron-withdrawing substituents on the conjugated side chain improve the conductivity from 10 to 10('7) times.