Noncoplanar rigid‐rod aromatic polyhydrazides containing Tröger's base

Abstract

AbstractA new Tröger's base‐containing aromatic dihydrazide, 2,8‐bis(carboxylic)‐6H, 12H‐5,11‐methanodibenzo‐[b,f] [1,5]‐diazocine dihydrazide, was prepared by the condensation of ethyl p‐aminobenzoate with hexamethylenetetramine in the presence of trifluoroacetic acid, followed by converting to the dihydrazide with a high yield and high purity. A series of novel aromatic polyhydrazides were prepared from the Tröger's unit containing dihydrazide and various aromatic diacyl chlorides via low‐temperature solution polycondensation in quantitative yields. All the polyhydrazides were amorphous and readily soluble at room temperature in polar organic solvents such as N,N‐dimethylacetamide and N‐methyl‐2‐pyrrolidone. These polymers could be solution cast into transparent, tough, and flexible films with good mechanical properties. They had useful levels of thermal stability associated with good glass transition temperatures (163–172°C), 10% weight‐loss temperatures in excess of 460°C, and char yields at 800°C in nitrogen higher than 39%. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011