Process for production of condensation polymers

A process for increasing the molecular weight of condensation polymers, the process comprising

• introducing a low molecular weight starting material to a reactor vessel, the vessel being equipped with a means for heating the material and further being equipped with a means for stirring the material, the vessel being further equipped with a means for introducing an inert gas, the vessel being further equipped with a means for removing the inert gas, the vessel being further equipped with a means for applying vacuum to the material while it is being stirred;
• heating the vessel either before, during, or after the introduction of the material, to a temperature at which a polycondensation reaction will proceed;
• stirring the material during the polycondensation reaction;
• during the polycondensation reaction, causing an inert gas to flow through the vessel over the surface of the material, the inert gas being at a pressure of no greater than 100 torr, and the rate of flow of the inert gas being from 10 to 100 ft./sec.;
• and
• removing the material when the molecular weight has undergone a desired increase.