Aromatic Polyesters Containing Ether and a Kinked Aromatic Amide Structure in the Main Chain: Synthesis and Characterisation

A novel bisphenol containing preformed multiple ether and amide linkages, N, N′-Bis (4-hydroxyphenoxyphenylene) isophthalamide (IPCD), was prepared and analysed by spectroscopic methods. New aromatic polyesters were prepared by polycondensation of IPCD with 1, 3-benzene diacidchloride and/or 1, 4-benzene diacidchloride. These obtained polyesters were structurally analysed by infra-red spectroscopy, measurements of inherent viscosity, wide-angle X-ray diffraction patterns, and thermal techniques such as differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and solubility tests in organic solvents. The synthesised polyesters had high molecular weights, as indicated by their inherent viscosities from 0.67 to 0.78 dL/g in N-methyl-2-pyrrolidone. The incorporation of ether and kinked aromatic amide moieties in the main polyester chains greatly affected the properties of these aromatic polyesters. The prepared polyesters readily dissolved in amide-type polar aprotic solvents and pyridine, indicating their solution processability. The DSC curves above the polyesters showed glass transition temperatures of 194 to 269 °C. TGA indicated that these newly obtained polyesters were stable up to 301 °C and retained a 39 to 48% weight at 900 °C. W-XRD analyses showed that the newly synthesised polyesters were amorphous, which is reflected in their solubility behaviour.

Novel organosoluble polyarylates based on diphenylamine-fluorene units

Two kinds of polyarylates with diphenylamine-fluorene units were synthesized from the bisphenol monomer “ N, N-di(4-hydroxyphenyl)-2-amino-9,9-dimethylfluorene” with two different benzenedicarbonyl chlorides. These polyarylates were highly soluble in N, N-dimethylacetamide, tetrahydrofuran, and chloroform and could be easily solution-cast into transparent films. Both of the polyarylates exhibited a couple of reversible redox with half-wave potentials in the range of 0.87–0.90 V. During the electrochromic process, the color of the film changed from colorless (neutral state) to grey green (oxidation state) with a high coloration efficiency of 242 cm2 C−1. Compared with the polyarylates prepared from terephthaloyl chloride, the polyarylates prepared from isophthaloyl chloride exhibited enhanced fluorescence because of the reduced charge-transfer effect. Furthermore, its fluorescence could be reversibly switched under the applied potentials.

Synthesis and characterization of new aromatic polyesters with a (4-phenoxyphenyl)phenylmethene linkage

A series of new aromatic polyesters containing a (4-phenoxyphenyl)phenylmethene linkage were prepared by phase transfer-catalyzed interfacial polycondensation of 1,1-bis(4-hydroxyphenyl)-1-(4-phenoxyphenyl)-1-phenylmethane with terephthaloyl chloride, isophthaloyl chloride, and so on. The inherent viscosities of the polyesters ranged from 0.62 to 0.90 dL/g, while number-average molecular weights were in the range of 30,500–35,500 g/mol. All the polyarylates were readily soluble in organic solvents such as dichloromethane, chloroform (CDCl3), tetrahydrofuran, meta-cresol, pyridine, N, N-dimethylformamide, N, N-dimethylacetamide, and 1-methyl-2-pyrrolidinone at room temperature, and could be cast into tough, transparent, and flexible films from their CDCl3 solutions. Wide-angle X-ray diffraction measurements revealed the amorphous nature of the polyarylates. These polymers showed glass transition temperatures ( Tgs) between 178°C and 240°C and decomposition temperatures at 10% weight loss ranging from 446°C to 483°C, while the initial degradation temperatures in the range of 410–435°C under nitrogen atmosphere. These new polyarylates exhibited higher Tgs and better solubility than bisphenol A-based analogues.

Synthesis and characterization of poly(ether ether ketone)s and poly(ether ether ketone ketone)s containing pendant biphenyl and naphthyl groups

New poly(ether ether ketone)s (PEEKs) and poly(ether ether ketone ketone)s (PEEKKs) containing pendant biphenyl and naphthyl groups were synthesized by nucleophilic substitution reaction of each of the four bisphenols viz., 1-(4-biphenylyl)-1,1-bis(4-hydroxyphenyl) ethane, 1-(4-biphenylyl)-1,1-bis(3-methyl,4-hydroxyphenyl) ethane, 4,4’-[1-(2-naphthalenyl)ethylidene] bis-phenol and 4,4’-[1-(2-naphthalenyl) ethylidene] bis-3-methylphenol with 4,4’-difluorobenzophenone and 1,3-bis(4–fluorobenzoyl)benzene in a solvent mixture of N,N-dimethylacetamide and toluene in the presence of anhydrous potassium carbonate. Inherent viscosities and number-average molecular weights of polymers were in the range of 0.42–0.86 dl/g and 2.40–7.55 × 104, respectively. PEEKs and PEEKKs were amorphous in nature and were readily soluble in a wide range of organic solvents and could be cast into flexible and tough films from chloroform solution. Glass transition temperature of PEEKs and PEEKKs were in the range of 180°C –200°C. T10 values of PEEKs and PEEKKs were in the range of 424°C–512°C in nitrogen atmosphere, indicating their good thermal stability.