General Electric Company

Jhy-Dou R Lo

William R Schlich

The present invention concerns a two-step extrusion melt polymerization process for making polyetherimides. The first step of the process involves producing a low molecular weight polymer by melt polymerizing a mixture containing a molar excess of one of the monomers. The second step involves melt polymerizing a mixture containing the low molecular weight polymer produced by the first step and a stoichiometrically sufficient amount of the second monomer to produce the desired polyetherimide polymer. Polymerization in two stages, rather than by the conventional one stage process surprisingly results in reduced extruder torque levels and improved throughput rates.

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Cupertino, CA, United States of America

Jhy-Dou R Lo