| 摘要 |
<p>PURPOSE: Polyimide polymers from 3,4,3',4'-biphenyltetracarboxylic dianhydride and 3,4,3',4'-benzophenonetetracarboxylic dianhydride and a diamine such as p-phenylenediamine exhibit a high glass transition temperature, high thermal oxidative stability and low moisture regain, useful for structural applications. CONSTITUTION: A polyimide ploymer having a glass transition temperature of greater than about 300°C comprises structural units derived from 3,4,3',4'-benzophenonetetracarboxylic dianhydride, 3,4,3',4'-biphenyltetracarboxylic dianhydride and one or more aromatic diamines, wherein the mole ratio of the structural units derived from 3,4,3',4'-benzophenonetetracarboxylic dianhydride to the structural units derived from 3,4,3',4'-biphenyltetracarboxylic dianhydride is in the range of from more than about 3.0/7.0 and up to about 4.0/1.0.</p> |
