Synthesis of polyanhydrides. II. New aromatic polyanhydrides with high melting points and fiber‐forming properties

Abstract

AbstractNew aromatic polyanhydrides with high melting points and fiber‐forming properties containing aliphatic chain or aliphatic chain and ether linkage between aromatic nucleus and carboxyl group in the main chain have been prepared. Contrary to the polyanhydrides of aliphatic dibasic acid prepared by CAROTHERS, it has been shown that these polyanhydrides possess high melting points and relatively stable properties towards hydrolytic degradation.Introduction of methylene group of methylene group and ether linkage between aromatic nucleus and carboxyl function enhances the flexibility of molecular chains, lowers melting points and causes the accumulation of phenylene nucleus along the polymer chain to form regular molecular structure of closes packing.Thus, polyanhydride of 1,4‐bis‐carboxymethyl benzene having a melting point 152°C. was obtained, while the polyanhydride prepared from hydroquinone‐0,0′‐diacetic acid with acetic anhydride has a melting point 158°C., and both of them show film‐ and fiber‐forming properties and good hydrolytic stability. The crystallinity of the polyanhydrides increases by annealing the stretched fiber at 100°C. 2.2‐bis(4‐hydroxyphenyl)propane 0,0′‐diacetic acid was polymerized with acetic anhydride and gives a linear polyanhydride of the melting point 196–202°C. which possesses fiber‐forming properties. Polyanhydrides thus obtained show a good stability towards thermal and hydrolytic degradations. Furthermore, the influence of the molecular structure on the physical properties of these polymers was discussed.