Novel Self-Dyed Wholly Aromatic Polyamide-Hydrazides Covalently Bonded with Azo Groups in Their Main Chains: 1. Structure-Property Relationships

Abstract

and increased with the para-phenylene units content. The polymers are partially soluble in DMAc, dimethyl formamide (DMF) and N-methyl-2-pyrrolidone (NMP). Their solubility increases with the introduction of meta-phenylene moieties into the polymer chains. The polymers exhibit a great affinity for water sorption. Their hydrophilicity increases as a function of the content of meta-phenylene rings incorporated into the polymer. Mechanical properties of the polymer films are improved markedly by substitution of para-phenylene units for meta-phenylene units. The completely para-oriented type polymer has the best thermal and thermo-oxidative stability relative to those of the other polymers.

Thermal and optical properties of aromatic polyamide–hydrazides modified with multiwalled carbon nanotubes

“…These weight losses can be attributed to cyclodehydration reaction of the polymers hydrazide groups into 1, 3, 4-oxadiazole rings as represented in Figure 4. [27][28][29][30][31][32][33] Also the residue of the solvent that makes strong physical interaction with the polymeric chains may explain the deviation of the weight loss at this stage from theoretical value (6-8%). Third, a steep weight loss took place at temperatures above 485 C for polymer I, 475 C for polymer II, and 480 C for polymer III and indicated the decomposition of the polymer containing 1,3,4-oxadiazole rings which were formed in the second stage.…”

“…All the FTIR spectra of these polymers (Figure 1) showed common absorption stretching vibration bands at the following wavenumbers: 3430-3260 cm À1 (intensive and broad) assigned the overlapped ¼NH and the possible interchain hydrogen bonding; 2300-2180 cm À1 (weak) is attributed to possible enol-type configuration of hydrazide and amide groups; 1660-1640 cm À1 (strong) corresponded to the amide carbonyl group; 1580-1600 cm À1 indicated the aromatic carbon-carbon double bonds; 1525-1515 cm À1 is due to ¼NH of amide II; 1500 cm À1 indicated carbon-carbon single bond in ring, and 1340, 1280, and 1250 cm À1 corresponded to carbon-hydrogen combined with ¼NH of amide III. 28,29 1 H-NMR analysis of the prepared polymers 1 H NMR spectra measured in DMSO for the as-prepared polymers, polymer I, polymer II, and polymer III, respectively (Online Supplemental File). For amide and hydrazide protons, the chemical shifts are observed between 10 ppm and 11 ppm.…”

Functional Aromatic Polyamides

“…Mohamed et al [132], synthetized twelve intrinsically orange colored aromatic azopolyamide-hydrazides. Polymers and copolymers were prepared from the reaction of 4-amino-3-hydroxybenzhydrazide and 3-amino-4-hydroxybenzhydrazide with 4,4-azodibenzoyl chloride and 3,3 -azodibenzoyl chloride.…”