Preparation and thermal properties of polyquinazolone containing 4‐substituted phenyl groups on the quinazolone ring

Abstract

Polyquinazolones containing 4‐substituted phenyl groups (H, Cl, CH3, CH3O, NO2) on the quinazolone ring were synthesized in m‐cresol and their thermal properties were studied by using dynamic thermogravimetry and isothermal weight loss in nitrogen and air. Polyquinazolones were synthesized with intrinsic viscosities in the range of 0.2–0.7 dL/g when phosphorus pentoxide was used as a catalyst. In TGA studies, there was a difference in the initial decomposition temperature of polyquinazolones with varying substituted groups. The introduction of substituted groups reduced oxidative thermal stability of the polymers. Furthermore, the thermal degradation mechanism was investigated by infrared spectrophotometry.

Synthèse de polyquinazolones à chaîne latérale fluorée

“…Les bisbenzoxazinones peuvent @tre obtenus par I'action des acides R,-C2H,C02H ou RF = C6F,, ou C,F,, et de I 3') La premikre Ctape est realisee dans la pyridine A 50 "C et conduit quantitativement au diamidoacide 2 a qui est un solide recristallisable dans le mClange N,N-dimCthylformamide (DMF)/acide acCtique (rapport volumique 2: 1) et qui fond a 243 "C aprks deux recristallisations. La dkshydratation de 2 a peut ttre realisCe par plusieurs methodes: le chlorure de p h~s p h o r y l e~-~) , le mClange chlorure de phosphonyle/pyridine et le mClange N,N-dimCthylacCtamide (DMA)/anhydride acCtique (Ac,O)/pyridine (rapport volumique 1 : 2 : 1) 7).…”

Preparation and properties of a new aromatic polyamide with an ethoxycarbonyl pendant group: Poly(4,4?-diamino-2?-ethoxycarbonyl-benzanilide terephthalamide)

“…In recent years, many thermally stable heterocyclic polymers have been reported [7][8][9][10][11][12][13][14][15][16][17][18] with the aim of overcoming the problems involved in processing PPTA. The polymer containing a benzoxazinone unit in the backbone chain is one of them and is known to have remarkable thermal stability.…”

Preparation and physical properties of poly(4,4?-diamino-3?-carbamoylbenzanilide terephthalamide) and poly(4,4?-diamino-3?-carbamoylbenzanilide isophthalamide) films

“…It widely is accepted that polymers containing a benzoxazinone or quinazolone unit in the main chain have excellent thermal stability 6–10. However, a heterocyclic polymer such as polyquinazolone is so brittle that its film has poor endurance and abrasion.…”