Pbzt/Polyamide Thermoplastic Micro-Composites - An Outgrowth of Molecular Composites Development

Abstract

Molecular composites are dispersions of rigid-rod polymer molecules in a matrix of flexible coil polymers, formed by the coagulation of a solution containing these components. Where there is aggregation of the rigid-rod molecules, such composites are called micro-composites (MC’s). These composites offer the potential for better economics and improvements in composite processing, and possibly performance, over conventional ‘string and glue’ composites. This paper describes work performed under contract to the U. S. Air Force to develop PBZT/thermoplastic molecular composites into a viable technology.

A commercially viable MC spinning and heat-treatment process has been defined based on a novel mixed solvent/quaternary solution technology developed by Du Pont. Advantages of this process include better economics, superior processing performance, and improved MC fiber tensile properties versus prior art. PBZT/polyamide MC fibers with strength/modulus of 332 ksi/29 Msi have been produced using this process. Adhesion equivalent to that obtained in conventional composites has been demonstrated. Uni-axial properties achieved to date compare favorably with conventional ‘string and glue’ PBZT/epoxy composites although compressive and shear strengths may be limiting factors in MC applications.