Pyrolysis Mass Spectrometry Analysis of Electrochemically Grafted Polyacrylonitrile with Thiophene

Abstract

In this work, structural and thermal analyses of a polythiophene/polyacrylonitrile (PTh/PAN) sample, prepared by electrochemical polymerization of thiophene onto a poly(acrylonitrile) coated anode, have been performed by a direct insertion probe pyrolysis mass spectrometry technique. The evolution profiles of PTh based products from PTh/PAN showed nearly identical trends with those recorded during the pyrolysis of pure PTh. However, when PAN based products were considered, contrary to the trends observed for pure PAN, evolution of HCN and the degradation products due to the homolytic cleavages of the polymer backbone continued throughout the pyrolysis indicating a significant increase in their production even at the final stages of pyrolysis. On the other hand, the yield of thermal degradation products associated with decomposition of the unsaturated cyclic imine segments decreased. A careful analysis of the data pointed out the presence of mixed dimers. Yet, because of the possible contributions of various products to the corresponding peaks, a copolymer formation cannot be confirmed.