Effect of the nature of acid dopant and oxidizer on the polymerization of aniline in the presence of polycarbonate dispersion

Abstract

The characteristics of aniline polymerization in the absence and in the presence of a dispersion of polycarbonate powder in dependence on the nature of acid dopant and oxidant has been studied. By monitoring the polymerization in situ by electronic spectroscopy and redoxometry allows the determination of the stages of formation of shell of polyaniline on the surface of polymer particles and the influence of the latter on the rate of these stages and of the process as a whole.The steady growth in the number of studies linked with polyaniline (PAN) is evidently connected with its complex of practically important properties (electric, optical, catalytic, sensor, electrochemical, etc.) [1,2]. However the potentially wide use of pure PAN is limited by its low stability and poor workability. These problems may be avoided in particular by the creation of composite materials coupling the properties of industrial polymers and PAN [3]. The nature of the coupled polymers (the matrix) determines to a considerable extent the characteristics of the composite with PAN as a result of the physico-chemical and physical interactions of all components of the system [3]. Correspondingly, the choice of the matrix polymer is determined by the requirements of the composite. In particular, for applications in which good optical characteristics are required in addition of strength, it is necessary to use matrix polymers with such properties, for example, polycarbonates (PC) [4].A very important factor that influence the features of the composite with PAN is its formability, which determine the distribution of PAN in the dielectric matrix, in particular the quality of the conduction of the network. In particular, simple mixing of the components in a melt or solution does not always lead to high dispersion of PAN as a result of incomplete or poor compatibility of the components [3]. In this case it is more effective to carry out polymerization of aniline in the dispersed matrix polymer which permits the creation of a thin layer of PAN on the surface of particles. A composite powder formed in this way with a nucleus-shell structure on treatment gives a material with uniform distribution with the nanodimensional structure of PAN [3,5]. The quality of the composite depends on such factors as the conditions for the polymerization, the size and possibly the nature of the covering of the particles, which defines the size and structure of the PAN shell. In this connection, as the basic objective of this work was the determination of the characteristics of the polymerization of aniline in the absence and in the presence of dispersed polymer powder (using PC as example) depending on the nature of the dopant acid and oxidant. EXPERIMENTALAniline (Merck) was purified by vacuum distillation and was stored at 5°C. PC powder, obtained by repricipitation from PC granules based on bisphenol A (Lexan, General Electric), was used as the disperse phase. The dopants used were 54 0040-5760/08/4401-0054 camphorsulfonic acid (CSA, Merck) and p-toluenesulfonic a...

Deep Impact of the Template on Molecular Weight, Structure, and Oxidation State of the Formed Polyaniline

“…The effects of the PC-PANI interaction on PANI properties (such as oxidation state, electronic structure, crystalline structure, and molecular weight), conductivity of the compression molded PC/PANI composite films, and parameters of the equation of percolation theory are discovered. Features of aniline polymerization in the PC dispersion dependent on the nature of acid dopant and oxidant have been presented elsewhere …”

“…Features of aniline polymerization in the PC dispersion dependent on the nature of acid dopant and oxidant have been presented elsewhere. 34 2. EXPERIMENTAL SECTION 2.1.…”

On the importance of interface interactions in core-shell nanocomposites of intrinsically conducting polymers

“…In order to find a way to realize such control, we monitored changes of the open circuit potential (OCP) and pH of the reaction media in the course of oxidative polymerization of aniline and heterocyclic monomers in absence and presence of other components. This approach enabled tracking changes in oxidation states of the conducting polymers forming the shells at the surface of the matrix (template) components [10][11][12]. Specifically, OCP and pH profiles for aniline polymerization can reveal characteristic time points corresponding to the most important stages of this process.…”

“…3b). Apparently, this may be due to the fact that surface-active acids form micelles in solution, which absorb the monomer and, probably, nanoparticles, thus creating the effect of a micro-reactor with an increased concentration of participants [12,14].…”