A process for producing low molecular weight, granular
polytetrafluoroethylene or modified polytetrafluoroethylene by suspension
polymerization of pressurized tetrafluoroethylene in an agitated reaction
vessel. The polymerization is conducted in aqueous medium in the presence
of a free radical initiator, and a telogen. The reaction vessel is
agitated during polymerization sufficiently to coagulate the
polytetrafluoroethylene or modified polytetrafluoroethylene. Low
molecular weight granular polytetrafluoroethylene or modified
polytetrafluoroethylene having a melt viscosity of less than about
1.times.10.sup.6 PaS powder is isolated directly from the reaction
vessel. The low molecular weight polytetrafluoroethylene or modified
polytetrafluoroethylene powder in accordance with the invention has a
melt viscosity of less than about 1.times.10.sup.6 PaS, a specific
surface area of less than about 8 m.sup.2/g, an extractable fluoride
level of about 3 ppm or less by weight, and a narrow molecular weight
distribution as indicated by a polydispersity index of about 5 or less.
The particles of low molecular powder have a weight average particle size
of about 2 to about 40 micrometers and the powder is substantially free
of particles having a particle size of less than about 1 micrometer. The
low molecular weight material so produced suitable for use as additives
to other materials such as inks, coatings, greases, lubricants, and
plastics.