Benzheterocycle–imide and amide–imide fibers derived from diacid chlorides containing preformed imide groups

Abstract

Fibers of benzoxazole–imide ordered copolymers were prepared by cyclodehydrating the amide–phenol units of precursor polyamide–o‐hydroxyimide fibers at 375°C in nitrogen. The precursor polyamide–o‐hydroxyimides were obtained by the reaction of 3,3′‐dihydroxybenzidine with diacid chlorides containing preformed imide rings. The benzoxazole–imide fibers are very thermally stable, especially with respect to retention of tensile properties after heat aging in air. For example, the benzoxazole–imide fibers after heating aging in air for 35 days retained 75% or more of their original tenacities and 50% or more of their original elongations to break. The original fibers did not have high tenacities, probably because of the rather extreme thermal treatment required to cyclodehydrate the amide–phenol units of the precursor fiber. The ultraviolet light stability of one benzoxazole–imide fiber was outstanding for a fiber of the polyheterocycle type: there was no loss in strength or elongation after 140 hr of exposure in a Fade‐Ometer. Fibers of ordered amide–imide polymers based on the same imide‐containing diacid chlorides used for the benzoxazole–imide polymers were also prepared. They were substantially less thermally stable than their benzoxazole–imide fiber counterparts, as expected.

Liquid-crystalline polyimides. 3. Fully aromatic liquid-crystalline poly(ester imide)s derived from N-(4-carboxyphenyl)trimellitimide and substituted hydroquinones

“…The dicarboxylic acid 4 was prepared from trimellitic anhydride and 4-aminobenzoic acid according to a modified procedure reported in the literature. 19 For reasons discussed below the chloro-substituted dicarboxylic acids 5 and 6 were also of interest. They were synthesized similarly from chloro-substituted 4-aminobenzoic acids and trimellitic anhydride.…”

Synthesis, Dielectric, and Photochemical Study of Liquid Crystalline Main Chain Poly(ester imide)s Containing Cinnamoyl Moieties

“…Synthesis of Monomers and Model Compounds. The synthesis of N -(4-carboxyphenyl) trimellitimide, N -(4-chlorocarbonylphenyl) trimellitimide chloride, N -(4-[2-carboxyethenyl]phenyl) trimellitimide, N -(4-[2-chlorocarbonylethenyl]phenyl) trimellitimide chloride, and p -phenylenebis(acrylic acid) dichloride were prepared according to the literature. − …”

“…trimellitimide chloride, and p-phenylenebis(acrylic acid) dichloride were prepared according to the literature. [22][23][24][25] Diethyl-p-phenylene Bis(acrylate), 1 (see Table 1). p-Phenylene bis(acrylic acid) dichloride (0.06 mol) was dissolved in an excess of dry ethanol (10 mL).…”

Polymers with Heterocyclic Rings in the Chain

“…The latter process often involves a soluble prepolymer. 104 It has been possible to ''tailor'' the properties of these copolymers towards, for example, enhanced thermal/thermo-oxidative stability or processability compared with the parent homopolyimide. However, although the comprehensive studies of Preston and Black 102 • 104 on ordered/limited ordered copolymers were directed specifically towards advanced fiber applications, none of the heterocyclic-imide copolymers have been marketed commercially except for an isoindoloquinazolinedione-imide material (PIQ) by the Hitachi Chemical Co. for electrical purposes.…”