Cyclopolycondensations. VI. Fully aromatic polybenzoxazinones from aromatic poly(amic acids)

Abstract

spaopldsNew high temperature aromatic polybenzoxazinones of high molecular weight have been prepared by the cyclopolycondensation of 4,4'diamhobiphenyl-3,3'dicarboxylic acid (I) with aromatic dicarboxylic acid halides (11). Thelow temperature solution polymerization techniques afforded poly(amic acid) (111) of high molecular weight in the first step. An open-chain precursor subsequently underwent thermal cyclodehydration along the polymer chain at 2W35OoC. in the second step, to give in quantitative yield a fully aromatic polybenzoxazinone (IV) of outstanding heat stability both in nitrogen and in air. The poly(amic acid) is soluble in N-methyl-Zpyrrolidone, and tough, transparent films can be csst from solution. Insoluble aromatic polybenzoxazinone f i l m s which possess excellent oxidative and thermal stability were obtained by the heat treatment of the polyamic acid. A detailed accouht of polymerization conditions in the low temper* ture solution polymerization of polybenzoxazinones is given, and the reaction mechanisms of cyclopolycondensation of poly(amic acids) and the formation of polybenzoxazinones are discussed. cyclopolycondensation of poly (amic acids) and the formation of polybenzoxazinone are discussed.

Cyclopolycondensation. XIII. Polymer Reactions of Polybenzoxazinones with Organic Base

“…This was prepared by the cyclopolycondensation of 4,4'- diamino-3,3' -biphenyldicarboxylic acid with 4,4'-oxydibenzoyl chloride in N-methylpyrrolidone, 4 and polyamide acid thus obtained was subsequently subjected to thermal cyclodehydration along the polymer chain at 300-350°C in the second step, to give in quantitative yield a fully aromatic polybenzoxazinone. These polybenzoxazinone films were used as the starting materials and as the authentic sample of polybenzoxaxinone in this experiment.…”

“…I, No. 4,1970 -scribed in previous papers 3 ' 4 by the reaction of anthranilic acid with benzoyl chloride in polyphosphoric acid: mp 120.5°C.…”

“…1, No. 4,1970 acetone, and the mixture was maintained at -86°C for 24 hr. After removing the excess liquid ammonia at 25°C the precipitate obtained at 98-% yield was extracted with NMP.…”

“…1, No. 4,1970 benzoxazinone, and that intramolecular dehydration occurs at 280°C to form polyquinazolone (Illa, Illb)-The· thermal stabilities of polyquinazolone (Illa, Illb) were measured either in nitrogen or in air by the thermogravimetric method, as shown in Figure 5. These quinazolone polymers have excellent thermal stability and decomposition begins from about 380°C in nitrogen.…”

“…In the course of studying cyclopolycondensation, 2 new aromatic polybenzoxazinones of high molecular weight were prepared by the cyclopolycondensation of 4,4' -diamino-3,3'-biphenyldicarboxylic acid with a variety of aromatic carbonyl compounds using the PPA solution polymerization technique 3 or the low temperature solution polymerization technique. 4 Polybenzoxazinone has the reactive benzoxazinone ring system in the polymer main chain, and it is presumed that the polymer reactions of polybenzoxazinone with nucleophilic agents provide polyamide derivatives from the ringopening reactions of the benzoxazinone ring.…”