Patent ID: 6919422
Filing Date: 2005-07-19
Classification: C08G,C08L,Y10T

Abstract:
1. A process to prepare a polyimide comprising structural units of the formula wherein “a” has a value of greater than 1, V is a tetravalent linker, and R is a substituted or unsubstituted divalent organic radical, which process comprises reacting an organic diamine monomer having a molecular weight from 100 to 500 with an aromatic dianhydride monomer with a molecular weight from 218 to 1000 wherein the molecular weight of the polyetherimide is controlled by addition of an aromatic monoamine capping agent of molecular weight 93 to 250; wherein said polyimide comprises less than 5 wt. % of impurities based on the weight of the polyimide, said impurities having a molecular weight of less than about 500 daltons and comprising structural units derived from at least one monomer unit or from at least one aromatic monoamine.