To provide a process for producing a multilayer stretched polytetrafluoroethylene articles, and porous articles.

A process of producing a multilayer polytetrafluoroethylene article 120 includes filling a pre-form 100 with two or more layers of polytetrafluoroethylene fine powders 102, 106, wherein at least one layer comprises a functional additive and at least one layer comprises a processing aid; disposing a separation layer 110 between the two or more layers, wherein the separation layer 110 is configured to provide structural integrity to each layer during filling; extruding the two or more layers to obtain a multilayer extrudate; removing the processing aid; and expanding the multilayer extrudate to form the multilayer stretched polytetrafluoroethylene article.