Abstract: The process comprises forming a mixture containing a thermoplastic material and a cross-linking agent and causing the mixture to enter a die head. A pressure is exerted on the mixture in the die head along the axis of the die head so as to sinter the mixture. The die head is heated to a temperature lower than the temperature at which the cross-linking agent becomes substantially decomposed so as to cause fusion of the mixture and produce a formed material. The formed material is passed through a bath of molten salt downstream of the die head. The temperature of the molten salt is such as to achieve the decomposition of the cross-linking agent and the cross-linking of the formed material. A device is described for carrying out the process.