Synthesis and properties of polyamides based on a spirobichroman bis(ether‐carboxylic acid)

Abstract

High molar-mass aromatic polyamides were obtained from 7,7'-bis(4-carboxyphenoxy)-4,4,4',4'-tetramethyl-2,2'-spirobichroman, a novel dicarboxylic acid monomer. by direct polycondensation reaction in N-methyl-2-pyrrolidone (NMP) with various aromatic diamines, wing triphenyl phosphite and pyridine as condensing agents. Polyamides having inherent viscosities of 0,73-I ,08 dL/g were obtained in quantitative yield. All the polyamides, even that derived from benzidine, are completely amorphous and readily soluble in a variety of organic solvents such as NMP, N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), and in-cresol. Their solutions can be cast into transparent. flexible and tough films. All the polyamides show distinct glass transitions in the range of 182-235°C on their differential scanning calorimetry (DSC) traces. The 10% weight loss temperatures in nitrogen and air are above 416 and 422°C. respectively.

Synthesis and characterization of aromatic polyamides based on a bis(ether-carboxylic acid) or a dietheramine derived from tert-butylhydroquinone

“…Recrystallization from DMF/methanol gave light yellow crystals (1 b) that were isolated by filtration, washed with water and dried. The yield was 16…”

“…However, their high softening or melting temperatures and limited solubility in most organic solvents, caused by their rigid structures, make their fabrication difficult. Therefore, current or prior attempts at solubilizing and processing these rigid-chain polymers have been made through the synthetic modification of basic rigid-chain structures by introducing flexibilizing linkages [4][5][6][7] , asymmetric units [8][9][10][11][12] , or bulky groups [13][14][15][16] into the backbone.…”

Synthesis and characterization of new diphenylfluorene-based aromatic polyamides derived from 9,9-bis[4-(4-carboxy-phenoxy)phenyl]fluorene

“…Fluorene-bisphenol 1 was prepared by a HCl-catalyzed condensation reaction of excess phenol with 9-fluorenone 20) . The new dicarboxylic acid monomer 3 having diphenylfluorene unit and two ether linkages was synthe-sized according to a well-developed method [21][22][23][24] as shown in Scheme 1. The intermediate dinitrile 2 was obtained from the nucleophilic fluorodisplacement of pfluorobenzonitrile with the potassium phenolate of fluorene-bisphenol 1 in DMF.…”

Preparation and characterization of aromatic polyamides from 4,4'-(2,6-naphthylenedioxy)dibenzoic acid and aromatic diamines

“…The direct polycondensation of aromatic diamines with dicarboxylic acids using a mixture of triphenyl phosphite and pyridine as condensing agent is a convenient method for the preparation of polyamides on a laboratory scale [17][18][19][20] . A series of new aramids (5a-p) were prepared from the diacid (3) and various aromatic diamines (4a-p) by this direct polycondensation technique (Scheme 2).…”