Syntheses of novel soluble carborane polyimides with ultrahigh thermal stability

Novel carborane polyimides were synthesized and studied. Aromatic meta -carborane diamines of different structures were initially prepared. Polymerization of these new diamines with the commercially available 4,4′-oxydiphthalic dianhydride led to meta -carborane polyimides with various structures and thermal properties. The amorphous polymers obtained are of moderate molecular weight and show good solubility in organic solvents. Thermal analyses of these polyimides reveal that they have moderate to ultrahigh thermal stability depending on their specific structures, with 5% decomposition temperatures ranging from 382 to 786 °C in nitrogen. Different thermal properties of these polyimides are observed when the analyses are performed in dry air, with 5% decomposition temperatures shifting to temperatures ranging from 388 to 1128 °C. Due to the ever-present requirement of higher performance polymers in fields like aerospace and defense, the methods developed here could be an impetus for the development of these industries. © 2015 Society of Chemical Industry