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Chemical polymerization of aniline in phenylphosphinic acid

Plesu Nicoleta (Institute of Chemistry of Romanian Academy, Timisoara, Romania)
Ilia Gheorghe (Institute of Chemistry of Romanian Academy, Timisoara, Romania)
Bandur Geza (University 'Politehnica' Timisoara, Romania)
Popa Simona (University 'Politehnica' Timisoara, Romania)

The chemical polymerization of aniline was performed in phenylphosphinic acid (APP) medium using ammonium peroxidisulfate as the oxidizing agent, at 0 ºC and 25 ºC. The yield of polyaniline (PANI) was about 60–69 %. The polymerization process required an induction time 8–10 times greater than in other acids (hydrochloric, sulfuric). The average density of the obtained polymer was 1.395 g cm-3 for PANI-salt and 1.203 g cm-3 for PANI-base. The acid capacity of PANI depends on the synthesis parameters and the maximum value was 15.02 meq/g polymer. The inherent viscosity of PANI was 0.662 dl/g at aniline/oxidant molar ratios >2 and 0 ºC. The oxidation state was a function of the synthesis parameters and lay between 0.553–0.625, as determined from UV-VIS and titration with TiCl3 data. The PANI samples were characterized by measurements of their density, inherent viscosity conductivity, acid capacity, FTIR and UV-VIS spectrum, and thermogravimetric data.

Keywords: chemical oxidation, aniline, phenylphosphinic acid, conducting polymers, polyaniline