Synthesis and properties ofpara-linked aromatic polycondensates containing 3,3′,4,4′-biphenyltetracarboxylic-N,N′-bis(4-amino-biphenyl) diimide units

Abstract

SUMMARY: Two new diamino monomers based on 3,39,4,49-biphenyltetracarboxylic dianhydride (BPDA) were synthesized and used in a low temperature polyamide polycondensation. High molecular weight homopoly(amide-imide)s and copoly(amide-imide)s were synthesized via in-situ silylation and investigated with respect to their solution, thermal, and film forming properties. All polymers are soluble in strong acids and most in amide type solvents. Inherent viscosities up to 7.4 dl/g in N-methyl-2-pyrrolidone (NMP)/LiCl were achieved. A methyl substitution in ortho-position to the imide group resulted in polymers possessing improved solubility and good thermal stability up to 500 8 C. Isotropic films can be prepared from solution.

Syntheses and properties of polyimides derived from diamines containing 2,5‐disubstituted pyridine group

“…That the BPDA‐based polyimides exhibited two T g may be attributed to the flexible BPDA moiety that can rotate around the main chain of polymers. As shown in Scheme , the kinked (cis) conformation of BPDA could be transformed into the extended (trans) conformation by rotation around the central single bond during the thermal process at elevated temperature 28. The pyridine ring has one nitrogen atom that decreases the symmetry elements of the polyimides containing pyridine units, so the polyimides based on the relative flexible dianhydride (BPDA) may show the transformation between four conformations at high temperature resulting in two glass transition temperatures.…”

Bismaleimide-diamine copolymers containing phthalide cardo structure and their modified BMI resins

“…In order to overcome them, the molecular design methodology was used by scholars all over the world to introduce new structures, such as naphthalene ring, [10][11][12][13][14] amides, 15 bisphenol, [16][17][18][19][20] an unsaturated five(or six)-membered ring, 21 fluorenyl 22,23 and oxadiazole, [24][25][26] into bismaleimide structure or added nucleophilic difunctional reagents to the maleic double bonds [27][28][29] with the aim of improving the processability and enhancing the fracture toughness of the corresponding cured without sacrificing thermostability and mechanical properties. However, this method has a low yield and a high cost.…”