The Effect of the Chain Sequence Distribution, Nature of Monomers and Temperature on the Electrical Conductivity of some Unsaturated Amide-Ester Copolymers

Abstract

Ten Amide-ester copolymers were synthesized, whereby the sequence distribution and the used dicarboxylic acids were varied. The electric conductivity of the copolymers are determined in the pure and doped states. The results showed that two factors are important in determining the conductivity levels: the flexibility of the polymer chains, and the efficiency of conjugation along the chains. Thus acidic units that give rise to coiled chains structure, and hence flexibile segments gives high conductivity compared with acid units that give rise to extended structure and rigid segments like terephthalic acid. The introduction of saturated units that interrupts the chains conjugation decrease the electrical conductivity of the polymers.The temperature dependence of the electrical conductivity (σ) of the investigated copolymers was studied in the temperature range (303-373K). A plot of ln (σ) versus (1/T) reveals that two regions with an inflection point at the glass transition temperature Tg of the polymers. The Tg of the investigated polymers determined by this method was found to be influenced by the nature of the repeating unit of the polymers and their sequence distribution.