Synthesis and characterization of Poly(p-phenylenediamine) and its derivatives using aluminium triflate as a co-catalyst

Abstract

A series of p-phenylenediamine (pPD), 2,5−dimethyl-p-phenylenediamine (dMe-pPD) and 2,3,5,6−tetramethyl-p-phenylenediamine (tMe-pPD) polymers were successfully synthesized in different polymerization conditions, using ammonium persulfate as an oxidant and aluminium triflate (Al(OTf)3) as a co-catalyst. The poly(p-phenylenediamine) (P(pPD)), poly(2,5−dimethyl-p-phenylenediamine) (P(dMe-pPD)) and poly(2,3,5,6−tetramethyl-p-phenylenediamine) (P(tMe-pPD)) polymers obtained were characterized by UV–vis, FT-IR, 1H and 13C NMR, WAXD, DSC and TGA. The addition of Al(OTf)3 to the polymerization reaction improved the polymerization yield of some polymers. In most solvents, significantly improved solubility of P(dMe-pPD) and P(Me-pPD) polymers was obtained compared to the P(pPD) polymers as a result of methyl side groups effects. The yield, structure and solubility of the polymers were shown to depend to a large extent on the polymerization conditions. The polymers displayed crystallization and melting transitions on DSC. The P(pPD), P(dMe-pPD) and P(tMe-pPD) polymers were found to have good thermal stability, as indicated by TGA results, and to decompose above 400°C in nitrogen.

Keywords

• aluminium triflate
• nmr
• oxidative polymerization
• p-phenylenediamine
• tga