Using aluminium triflate as a co‐catalyst for the polymerization of o‐phenylenediamine and its derivatives

Abstract

Aromatic diamine monomers, including o‐phenylenediamine (oPD), 4‐methyl‐o‐phenylenediamine (4Me‐oPD), 4,5‐dimethyl‐o‐phenylenediamine (dMe‐oPD) and 4‐(tert‐butyl)‐o‐phenylenediamine (tBu‐oPD), were polymerized by chemical oxidation using ammonium persulfate as an oxidant. Aluminium triflate (Al(OTf)3) was also used for the first time as a co‐catalyst under various reaction conditions for the polymerization of oPD derivatives. The polymerization yield was improved when Al(OTf)3 was introduced to the polymerization reaction for most polymers. The solubility of poly(4‐methyl‐o‐phenylenediamine) (P(4Me‐oPD)), poly(4,5‐dimethyl‐o‐phenylenediamine) (P(dMe‐oPD)) and poly(4‐(tert‐butyl)‐o‐phenylenediamine) (P(tBu‐oPD)) polymers was improved compared with the poly(o‐phenylenediamine) (P(oPD)) polymers in most common solvents. The homopolymers obtained were characterized by Fourier transform IR spectroscopy, UV−visible spectroscopy, 1H and 13C NMR, wide‐angle X‐ray diffraction, DSC and TGA. The results showed that the yield, solubility and structure of the polymers are significantly dependent on the polymerization conditions. DSC measurements indicated that the polymers exhibited melting and crystallization transitions. The polymers also showed good thermal stability and decompose above 400 °C in nitrogen. © 2013 Society of Chemical Industry

Microcapsule-based self-healing materials: Healing efficiency and toughness reduction vs. capsule size

“…For the central grooved section, 20 wt.% of microcapsules were dispersed within the matrix material (Epikote 828) using a high shear stirrer at 100 rpm for 10 min. At the end of the dispersion process, Epikure 541 hardener at a 100:50 ratio and 3 wt% aluminum triflate (as catalyst for the healing process [30,38,39]) were added to the mixture. The mixture was then degassed 2 times for 2 min.…”

Modeling the spectral properties of poly(x‐phenylenediamine) conducting polymers using a combined TD‐DFT and electrostatic embedding approach

“…Since a comprehensive experimental investigation of the optical properties of all three systems is unfortunately not available from a single literature work, data have been collected from several experimental papers. 30,31 Overall, the available experimental UV-Vis spectra of poly-PDA polymers all exhibit two strong absorption bands located the first at 270, 276 and 290 nm and the second at 462, 459, and 405 nm for (poly-(o)-PDA), (poly-(m)-PDA) and (poly-(p)-PDA), respectively. The higher energy band has been experimentally attributed to π-π* transitions localized on the aminobenzoic fragments while the latter is ascribed to the presence of phenazine fragments within the chains.…”

“…The higher energy band has been experimentally attributed to π-π* transitions localized on the aminobenzoic fragments while the latter is ascribed to the presence of phenazine fragments within the chains. [29][30][31][32] For poly-(p)-PDA there are some experimental reports indicating also the presence of a broad peak around 636 nm attributed to the occurrence of imine containing fragments. 29 Indeed, the presence of different fragments, including imine or diazo fragment for instance, 29 in variable relative ratio within each polymers chain cannot be excluded depending on experimental conditions such as solvent, acidity of the reaction environment, oxidizing agent and/or catalysts used for the synthesis.…”

“…The computed optical spectra of poly‐( o )‐PDA, poly‐( m )‐PDA and poly‐( p )‐PDA oligomers are reported in Figure 4 together with available experimental band maxima. Since a comprehensive experimental investigation of the optical properties of all three systems is unfortunately not available from a single literature work, data have been collected from several experimental papers 30,31 …”

“…Simulated UV–Vis absorption spectra (solid curve) of PDA oligomers and experimental absorption band positions (blue dashed line) of poly‐( o,m,p )‐PDA 29–31 …”