From Parkinson's chemotropic agent l-dopa to thermally resistive carbonaceous nanocomposite of a new catechol-grafted poly(amide-imide). (1st August 2018)

• Record Type: Journal Article
• Authors: Ahmadi, Mehdi; Rad-Moghadam, Kurosh; Hatami, Mehdi
• Is Part Of: Polymer. Volume 149(2018)
• Page Start: 1
• Page End: 12
• Publication Date: 2018-08-01
• Subjects: l-Dopa -- Catechol containing polymer -- Nanocomposite -- Thermal stability -- Chiral poly(amide-imide); Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2018.06.053
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: N, N′-Pyromellitoyl-bis-L-(3, 4-dihydroxyphenyl)alanine was synthesized, as a new diacid monomer, from condensation reaction of l -dopa and pyromellitic anhydride. Polycondensation of this chiral monomer with the commercially available 4, 4′-diaminodiphenylsulfone was achieved by using triphenylphosphite, as coupling agent, and calcium chloride, as dehydrating agent, in a mixture of N -methyl-2-pyrolidone and pyridine, giving a fairly high yield of a novel optically active poly(amide-imide) (PAI). This catechol containing PAI shows excellent adhesion to carboxylated carbon nanotubes, as forcing it to adopt a semi-crystalline structure in the interface with the nanotubes and thereby results in formation of a thermally stable and nearly homogeneous nanocomposite. FT-IR study revealed that much of this adhesion arises from H-bonding of the carboxylated nanotubes with the carbonyl groups of the PAI. The uniform distribution of the nanotubes in the PAI matrix was confirmed by FE-SEM and TEM micrographs of their nanocomposite. Thermogravimetric analysis of the PAI and its nanocomposites with 5, 10, and 15 wt% of carboxylated carbon nanotubes indicates that their decomposition occur in the temperature range of 347–365 °C. The limiting oxygen indices for the PAI and its nanocomposites were found to be in the range of 37.9–43.1. The polymer and its nanocomposites were characterized by additional techniques. Graphical abstract: A novel thermally stable catechol grafted poly(amide-imide) was synthesized by starting from l -dopa. The chiral polymer has shown great affinity for adsorption onto carboxylated carbon nanotubes to form homogeneous composites with enhanced thermal stability. Image 1 Highlights: A novel chiral catechol containing poly(amide-imide) was synthesized from l -dopa. The polymer has shown excellent affinity for adsorption onto carboxylated carbon nanotubes. As a result of cohesive forces, the polymer adopts a semi-ordered conformation at interface with the nanotubes. The polymer gained enhanced thermal stability by formation of composites with carbon nanotubes.