ARTICLES INCLUDING EXPANDED POLYTETRAFLUOROETHYLENE MEMBRANES WITH SERPENTINE FIBRILS AND HAVING A DISCONTINUOUS FLUOROPOLYMER LAYER THEREON

摘要

Articles including expanded fluoropolymer membranes having serpentine fibrils are provided. The fluoropolymer membranes exhibit high elongation while substantially retaining the strength properties of the fluoropolymer membrane. The membrane may include a fluoropolymer and/or elastomer. Additionally, the article has an elongation in at least one direction of at least about 100% and a matrix tensile strength of at least about 50 MPa. The article may be formed by (1) expanding a dried, extruded fluoropolymer tape in at least one direction to produce an expanded fluoropolymer membrane and (2) retracting the expanded fluoropolymer membrane in at least one direction of expansion by applying heat or by adding a solvent. The application of a tensile force at least partially straightens the serpentine fibrils, thereby elongating the article. The expanded fiuoropolymer membrane may include a microstructure of substantially only fibrils. The membranes may be imbibed with an elastomeric materia! to form a composite.