| 摘要 |
<p>A method of producing a colorless, high molecular weight polyimide of the formula: <CHEM> wherein R is <CHEM> is disclosed. The polymer is prepared from substantially equimolar amounts of 2,2 min -bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride and a diamine selected from the group consisting of 2,2 min -bis(4-aminophenyl) hexafluoropropane and 2,2 min -bis(3-aminophenyl) hexafluoropropane, by way of a low-temperature, substantially isothermal polymerization process followed by cyclization. In preferred embodiments, substantially analytically pure reactants are utilized.</p> |
