Poly(amide-imide)s obtained from 3,5-diamino-N-(thiazol-2-yl)-benzamide and dicarboxylic acids containing various amino acid units

Abstract

This study reports a green approach toward the synthesis of novel optically active poly(amide-imide)s (PAI)s bearing thiazole moiety, which was formed by the polycondensation reaction of 3,5-diamino-N-(thiazol-2-yl)benzamide and various diacids containing natural amino acids in molten tetrabutylammonium bromide. Diamine monomer was synthesized by the reduction of 3,5-dinitro-N-(thiazol-2-yl)benzamide in methanol using iron oxide hydroxide as a catalyst. This catalyst can rapidly reduce the sulfur and azo-containing aromatic nitro compounds to the corresponding amines in high yield by employing hydrazine hydrate as a hydrogen donor. Chiral diacid monomers were synthesized in high yield through the reaction of pyromellitic dianhydride and amino acids (L-isoluecine, S-valine, S-methionine, and L-phenylalanine) in acetic acid. The direct polymerization reactions of these monomers provided a series of new optically active PAIs with inherent viscosities in the range of 0.20-0.28 dL g À1 . The obtained polymers were characterized by Fouriertransformed infrared spectroscopy, specific rotation measurements, and the representative of them by proton nuclear magnetic resonance and elemental analysis techniques.

Structural Characterization and Thermal Properties of Chiral Poly(amide-imide)/Modified MgAl Layered Double Hydroxide Nanocomposites Prepared via Solution Intercalation

“…The incorporation of a chiral unit into the polymer backbone was obtained by measuring the specific rotations of ½a 25 D ¼ À26:16 (0.05 g in 10 mL of DMF). Chemical structure and purity of this polymer was confirmed in our previous study [46] .…”

Efficient Preparation of New Nanostructured Poly(Amide-Imide)s Condensed From 3,5-Diamino-N-(Thiazole-2-yl)Benzamide and Various N-Trimellitylimido-L-Amino Acids

“…[30] Chiral diacid monomers 7a-7d were prepared by the condensation reaction of one equimolar of TMA and one equimolar of different natural amino acids (S-valine, L-leucine, L- methionine, and L-isoleucine) in refluxing acetic acid, as shown in Scheme 2. [31] Polymer Synthesis In this work, a series of novel optically active and nanostructured PAIs (8a-8d) were synthesized by the direct polycondensation reaction of diacids 7a-7d with diamine 4 in molten TBAB as a reaction medium and TPP as activating agent (Scheme 2). The synthesis and some physical properties of these novel optically active PAIs are listed in Table 1.…”

“…[31] In an experiment, 14 g iron (III) chloride dissolved in 41 mL of distilled water and adding NaOH to the solution to bring the pH to 7. Then the suspension was heated to 60 • C and maintained at this temperature for 12 h. After centrifugation and drying the catalyst was redispersed and milled to a fine powder.…”

The fabrication and characterization of nanocomposites containing new poly(amide–imide) based on 4,4-methylenebis(3-chloro-2,6-diethyl trimellitimidobenzene) and carboxylic acid-functionalized multiwalled carbon nanotubes

“…14 ILs, which have been widely named as ''green solvents,'' have many advantages, such as extremely low toxicity and volatility, excellent thermal and chemical stability, high ionic conductivity, and ease of recycling. [15][16][17][18][19][20][21][22][23] The main objectives of this article are to evaluate the morphology of the carboxyl-modified multiwalled carbon nanotubes (CA-MWCNTs) in a PAI matrix. First, the PAI having good thermal stability as well as good solubility in polar organic solvent was synthesized.…”