New Polymeric Materials Expected to Have Superior Properties for Space-Based Use

摘要

The properties of electrically conducting, semiconducting and semiinsulating polymers were surveyed and their conduction mechanism, mechanical properties, and suitability for spacebased use evaluated. Correlations between molecular structure, conductivity, and mechanical properties were drawn, and a comprehensive model of electrical conductivity in organic polymers was formulated. Although the most widely studied electrically conducting polymers are not robust enough for most space-based uses, several commercial materials, including pyrolyzed Kapton and polyvinyl carbazole, appear to have the necessary combination of electrical, thermal, and mechanical properties. The main obstacle to the selection of new or modified materials for spacecraft use is the lack of strength, thermal stability, and radiation resistance--not their conductivity. Several synthesis procedures are identified that would raise the value of these properties to acceptable levels for materials that have the required electrical properties. The wide range of data reported in the literature can be reconciled by a theory of conductivity in which the limiting feature is the rate at which electrons are transferred between localized charges states. Some of the new polymers identified by this model have been prepared. They possess relatively high electrical conductivities and, unlike the majority of electrically conducting polymers, are processable in organic solvents.