Polymer, Vol.34, No.18, 3940-3947, 1993
Novel Wholly Aromatic Polyamide-Hydrazide .3. Preparation and Characterization of Semiconductors from Poly(4-(Terephthaloylamino) Salicylic-Acid Hydrazide)-Metal Chelates
The effect of the introduction of metal on the physical and electronic properties of a functional polymer, poly[4-(terephthaloylamino)salicylic acid hydrazide], PTASH, has been investigated. Cu(II), Ag(I), Ni(II) and Co(II) chelates of the polymer were prepared. The results revealed that metal ions were chelated with the PTASH repeating unit in a ratio of 1:1. The structure of the resulting chelates was determined by elemental analysis and i.r. spectroscopy. The chelates showed good solubility in several common organic solvents. Thermal gravimetric analysis showed that the chelates are characterized by high thermal and thermo-oxidative stabilities and the degradation temperatures ranged from 510 to 585-degrees-C in air and from 555 to 610-degrees-C in a nitrogen atmosphere. The chelates were found to become electronic conductors upon treatment with various reducing agents. Their electrical surface resistivities ranged from 5.3 x 10(5) to 0.5 x 10(-2) OMEGA mm-2 and were affected by the amount of metal incorporated onto the polymer chains. The electrical conductivities of the reduced chelate films are attributed to the formation of a metallic surface layer by the action of reducing agents. This layer is illustrated not only by the lustrous metallic appearance of the chelate film surfaces but is also confirmed by X-ray diffraction and SEM. Further, all the metal chelates studied here are flexible and possess higher tensile strength than the non-chelated PTASH.