A method for producing thermoplastic elastomer is disclosed and comprises the step of: blending a mixture including particles of vulcanized rubber material and a molten thermoplastic material such that the rubber material is subjected to mechanical shearing forces and the surfaces of the rubber particles undergo homolytic bond scission to form chains of free radicals which cross-link with the thermoplastic material. Apparatus for carrying out the method, elastomers produced by the method and articles produced from the elastomers are also disclosed.