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Journal ArticleDOI

Synthesis and properties of poly(benzoxazines): Poly[6,6′-methylene(4H-3,1-bibenzoxazine) 2,2′-diylphenylenes

01 Oct 1980-Polymer Bulletin (Springer Nature)-Vol. 3, Iss: 4, pp 191-196
TL;DR: In this paper, a new class of benzoxazine polymers were synthesised from bis(4-amino-3-hydroxymethylphenyl)methane with substituted phthalic acids by solution poly-condensation in polyphosphoric acid.
Abstract: A new class of benzoxazine polymers were synthesised from bis(4-amino-3-hydroxymethylphenyl)methane with substituted phthalic acids by solution poly-condensation in polyphosphoric acid. The model compound bis(4H-3,1-benzoxazine)2,2′-p-phenylene was also synthesised. The polymere were characterised by UV and IR spectra, viscosity measurements and thermal analysis.
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Journal ArticleDOI
TL;DR: The melting polycondensation of aromatic tetraamines and the diphenyl esters of aromatic dicarboxylic acids was developed as a general procedure of wide applicability as mentioned in this paper.
Abstract: Wholly aromatic polybenzimidazoles were synthesized from aromatic tetraamines and difunctional aromatic acids and characterized as new thermally stable polymers. The melt polycondensation of aromatic tetraamines and the diphenyl esters of aromatic dicarboxylic acids was developed as a general procedure of wide applicability. Polybenzimidazoles containing mixed aromatic units in the chain backbone were prepared from 3,3′-diaminobenzidine, 1,2,4,5-tetraaminobenzene and a variety of aromatic diphenyl dicarboxylates. Phenyl 3,4-diaminobenzoate could also be polymerized by melt condensation to give poly-2,5(6)-benzimidazole. The polymers were characterized by a high degree of stability, showing great resistance to treatment with hydrolytic media and an ability to withstand continued exposure to elevated temperatures. Most of the polymers were infusible, but some had melting points above about 400°C. Many of the polymers exhibited no change in properties on being heated to 550°C. and showed a weight loss of less than 5% when heated under nitrogen for several hours to 600°C. The polymers were soluble in concentrated sulfuric acid and formic acid, producing stable solutions. Many of the polymers were soluble in dimethyl sulfoxide and some also in dimethylformamide. The inherent viscosities of a number of polymers in 0.5% dimethyl sulfoxide solution ranged from approximately 0.4 to 1.1. The higher polymers could be cast into stiff and tough films from formic acid and dimethyl sulfoxide solutions.

439 citations

Journal ArticleDOI
TL;DR: In this article, complete aromatic polybenzothiazoles possessing superior oxidative and thermal stability have been prepared from aromatic bis(o-mercaptoamines) and aromatic dicarboxylic acids and benzothiazole forming derivatives thereof.
Abstract: Completely aromatic polybenzothiazoles possessing superior oxidative and thermal stability have been prepared from aromatic bis(o-mercaptoamines) and aromatic dicarboxylic acids and benzothiazole forming derivatives thereof. The condensations were performed in N,N-diethylaniline and polyphosphoric acid. The former solvent gave meltable, low molecular weight prepolymers which were advanced to high molecular weight polybenzothiazoles by heating in the solid state. The course of the reaction was follwed by removing samples periodically and determining the polymer melt temperature, inherent viscosity, specific extinction coefficient and observing changes in the infrared spectrum. In polyphosphoric acid, relatively high molecular weight polybenzothiazoles were obtained after a short reaction period. The polybenzothiazoles exhibited average TGA weight losses of 6% to 600°C. in static air. The maximum glass transition temperature obtained for poly-2,2′-(m-phenylene)-6,6′-bibenzothiazole was 910°C. Most of the polybenzothiazoles were soluble in concentrated sulfuric acid and 0.3% solutions exhibited inherent viscosities as high as 1.51.

11 citations