Preparation and properties of novel aromatic polyamides and polyimides lacked with dendritic fragments

The polycondensation of polymerizable diamines bearing two generations of Percec-type dendritic blocks with dianhydrides led to the formation of novel aromatic polyamic acids that then were converted into a series of novel aromatic polyimides jacked with dendritic fragments. Their solubility in organic solvents was improved remarkably by the introduction of the dendritic fragments, especially in the case of the polyamides and polyamic acids, and the polymers were soluble in normal solvents such as ethyl acetate, acetone, and chloroform. Their thermal properties were investigated with differential scanning calorimetry and thermogravimetric analysis. The glass-transition temperatures of these polyamides were lower than those of the conventional aramids. All of the polyamides, polyamic acids, and polyimides bearing the dendritic fragments showed two decomposition stages. (C) 2000 John Wiley & Sons, Inc.