Soluble, Rigid-Rod Polyamide, Polyimides, and Polyazomethine with Phenyl Pendent Groups Derived from 4,4‘‘-Diamino-3,5,3‘‘,5‘‘-tetraphenyl-p-terphenyl

Abstract

The reaction of 4,4‘-(1,4-phenylene)bis(2,6-diphenylpyrylium tetrafluoroborate) with nitromethane afforded 4,4‘‘-dinitro-3,5,3‘‘,5‘‘-tetraphenyl-p-terphenyl, which was catalytically hydrogenated to the corresponding diamine. The latter was used as starting material for the preparation of new rigid-rod polyamide, polyimides, and polyazomethine bearing phenyl pendent groups as well as the respective model compounds. Characterization of polymers was accomplished by inherent viscosity measurements, elemental analysis, 1H-NMR, 13C-NMR, X-ray, DTA, TMA, TGA, and isothermal gravimetric analysis. The polymers were amorphous and soluble in polar aprotic solvents. Polyamide showed an outstanding solubility, being soluble even in o-dichlorobenzene and chloroform. Polyamide displayed T g and softening temperature at 135 and 155 °C, respectively, whereas other polymers showed only T g above 265 °C. The polymers were stable up to 397−441 °C in N2 and 344−363 °C in air and afforded anaerobic char yields of 68−77% at 800 °C. In addition, the thermal stability of polyazomethine was investigated as a function of the curing time.

Synthesis and identification of organosoluble polyimides: thermal, photophysical and chemiluminescence properties

“…[6][7][8] Significant synthetic efforts in the area of high-performance polymers have been focused on improving the processability and solubility of PIs through the design and synthesis of new monomers. Various structural modifications can be made to the PI backbone to modify the polymer properties, such as insertion of flexible linkages on the main chain, 9-13 use of noncoplanar 14 or asymmetric monomers [15][16][17][18][19] and incorporation of pendant groups in the polymer backbone, [20][21][22][23][24][25][26][27][28][29] with results including lower interchain interactions or a reduced polymer chain stiffness. Depending on the type and amount of structural modifications, melting temperatures can be lowered and solubility improved, resulting in processable materials.…”

Synthesis, characterization and electrochemical properties of poly(phenoxy-imine)s containing carbazole unit

“…To understand the electronic structure of conjugated polymers it is essential to establish the relative positions of the characteristic electronic energy levels such as the highest occupied molecular orbital (HOMO or п level), the lowest unoccupied molecular orbital (LUMO or п), and the associated energy parameters [25,26]. The oxidation peaks in cyclic voltammograms probably correspond to the oxidation of hydroxyl groups to form phenoxy radicals.…”

Synthesis and Characterization of Poly(azomethine ester)s with a Pendent Dimethoxy Benzylidene Group

“…Thus, it is clear that various structural changes should be made in the poly(azomethine ester)'s chain to obtain better solubility and its application in various fields [9][10][11][12][13][14][15]. Some of the reported methods to improve the processability of conjugated poly(azomethine)s are by incorporation of unsymmetrical or symmetrical substitutions in the main-chain aromatic benzene rings with flexible alkyl or alkoxy side chains and reversible Lewis acidbase complexation [16][17][18][19]. Moreover, it has been already found that introduction of groups with sp 3 -hybridized atoms (-CR 2 -), ether linkage, and pendant phenyl groups can improve the solubility of polyesters [20][21][22][23][24][25][26].…”