Abstract: A method for obtaining low molecular weight polytetrafluoroethylene (PTFE) comprising the following steps: provision of high molecular weight PTFE; arrangement of said high molecular weight PTFE in a chamber, delimited by a gas barrier and containing a controlled atmosphere with an amount of oxygen comprised from 0.005% to 0.5% by volume; hermetically sealing of said chamber containing said high molecular weight PTFE; irradiating said PTFE into said hermetically sealed chamber to obtain said low molecular weight PTFE.

Abstract: A composition based on PTFE, in the form of a paste, obtained by mixing together a PTFE powder, with mineral fillers, selected from PbO, Pb powder, aluiminum silicates, graphite, MoS.sub.2, a resin of high adhesive properties, in particular an epxoy resin; solvents with good wetting properties for the solid ingredients and vaseline to impart to the paste the suitable degree of viscosity, said paste being applicable in a very thin layer to porous bronze bearings or supports, and suited for forming a self-lubricating layer, after a thermal treatment of the said PTFE on said bearings.