Synthesis and properties of processible copolymer microparticles from chloroanilines and aniline

Two series of functional copolymer microparticles were simply synthesized via an oxidative polymerization of o- and m-chloroanilines (OC and MC) and aniline (AN) in HCl aqueous medium, for a detailed comparison between OC/AN and MC/AN copolymers. The polymerization characteristics, structures, and properties of the copolymers were systematically studied by gel permeation chromatographic, IR and UV-visible spectroscopic, wide-angle X-ray diffractive, and thermogravimetric techniques. The results showed that a small amount of AN can efficiently activate the oxidative polymerization of MC monomer although MC monomer can not homopolymerize oxidatively. A non-linear variation of the polymerization effect, molecular weight, and properties of the copolymers with the comonomer ratio suggests that the OC/AN and MC/AN polymers formed are genuine copolymers rather than a mixture of the corresponding homopolymers. The resultant copolymers show a remarkably enhanced solubility, a colorful solvatochromism and an improved processibility in comparison with polyaniline. The OC/AN copolymers demonstrate a faster polymerization rate, narrower molecular weight distribution, and higher conductivity, but have a lower polymerization yield, molecular weight, thermostability, and air-separation capability than the MC/AN copolymers.