properties of the MQ/solution of sodium in liquid ammonia treated PTFE composite decreased compared with those of the untreated one. To investigate the production potential of extrusion process, an electric wire was extruded with MQ/ PTFE/FMQ composites. During the curing process, volatile molecules lead to bubble and void formation of extruded layer depending on the filler shapes. The spherical PTFE powder was suitable for extrusion process. (D) 2007 Wiley Periodicals, Inc.Various micronized polytetrafluoroethylene (PTFE) powders were compounded with silicone rubber (MQ) and mechanical properties of the MQ/PTFE composites were evaluated. The fracture surface morphologies of prepared composites were also investigated using scanning electron microscopy (SEM). At a level of only 5 wt %, the fractured surface of MQ/PTFE composites show layered structure morphology. This structure effectively improves the tear strength of MQ but it also led to lower the tensile properties of the composites. The addition of fluorosilicone rubber (FMQ) as compatibilizer, tensile and tear strength of the composites improved considerably. However, tensile