Abstract: The improvement of passing an inert, preferably vaporizable and condensible, liquid material through or over a polyester molten mass in a polymer reactor to further increase surface area-to-volume ratio and/or lower the partial pressure of vaporous products of condensation so that viscosity of the polymer is increased at a substantially greater rate in the same residence time is taught for the prior art condensation process in a film-forming reactor at temperatures of 275.degree. C. to 300.degree. C., pressures of 0.1 to 760 Torr, and residence times of 0.1 to 6 hours. A polymer having an intrinsic viscosity above 0.65, preferably over 0.7, is produced.

Abstract: Particulate polytetrafluoroethylene dispersion resin characterized by high molecular weight, relatively large particle size, uniform spherical particle shape and narrow particle size distribution, which is suitable for making stable concentrated aqueous polytetrafluoroethylene dispersions of concentrations higher than heretofore available, is made by polymerization of tetrafluoroethylene in aqueous dispersion in the conjoint presence of liquid octafluorocyclobutane and certain polyfluorinated carboxylic acid salt dispersing agents, using water-soluble peroxide initiators.

Abstract: Particulate polytetrafluoroethylene dispersion resin characterized by high molecular weight, relatively large particle size, uniform spherical particle shape and narrow particle size distribution, which is suitable for making stable concentrated aqueous polytetrafluoroethylene dispersions of concentrations higher than heretofore available, is made by polymerization of tetrafluoroethylene in aqueous dispersion in the conjoint presence of fluid octafluorocyclobutane and certain polyfluorinated carboxylic acid salt dispersing agents, using water-soluble peroxide initiators.