Abstract
The main aim of this paper is to study the thermal stability of some aromatic copolyethers containing a tetramethylenic spacer. The polymers were synthesized using a phase transfer catalysis technique, starting from 1,4’-dichlorobutane and various bisphenols: 4,4’-dihidroxyazobenzene, 4,4’-dihidroxy-diphenyl, bisphenol A and 2,7-dihidroxynaphthalene. It was studied the correlation between structure - thermostability - degradation mechanism. There were used thermodynamic, thermogravimetric methods, derivative thermogravimetry and differential thermal analysis for the evaluation of the kinetic characteristics and for establishing the correlation between activation energies - the conversion rate. The thermal stability is determined by the azo moieties within the main chain. The thermostability of the copolymer is improved by raising the content of the co-monomer with the highest thermostability. The degradation mechanism derives from successive reactions, with a nucleation complex process. Keywords: thermal stability, liquid crystalline copolyether, azobenzene, thermal degradation mechanis