Architectural PTFE-Coated Glass Fabrics—Their Structure and Limitations

Abstract

PTFE-coated glass fabrics, used as membranes for advanced architectural tension structures, offer advantages over conventional low cost coated fabrics in terms of their chemical stability, mechanical properties, and expected service life. These ma terials have a high shear stiffness, however, and the brittle behavior of glass fibers necessitates careful handling. The structure and performance of several commercial PTFE-coated fabric systems were investigated by scanning electron microscopy, mechanical testing, and weathering in artificial and natural environments. Acoustic emission analysis demonstrated that these flexible coated fabrics respond to stress in a predictable manner similar to rigid composite materials. The susceptibility of these materials to bending and fatigue loads was confirmed in flexure tests. Sintered PTFE coatings contain pinholes and regions of surface rupture around glass sphere filler particles. Exposure of coated fabrics to hot moist environments and to the natural environment, when loaded uniaxially outdoors, results in further surface damage. PTFE coatings are likely to incur progressive surface damage during envi ronmental exposure in architectural membranes, leading to possible damage to the underlying glass fabric.