Thermal and Mechanical Properties of Microchannel Core Sandwich Composites for Space Structures

摘要

Human space travel and off-world colonization will require lightweight composite materials which can provide both low thermal conductivities (in the range of 10-50 mW/m·K) and strong mechanical properties (capable of safely supporting internal habitat pressures of 100 kPa). A technique has been developed which permits the introduction of micro-and nano-scale hollow channels into a polymer matrix, in controlled volume fractions and configurations, which allows for optimization of both thermal insulation and mechanical properties. By varying the volume fraction and/or orientation of the micro-channels, control over final density, effective thermal conductivity, and mechanical performance can be achieved (the tensile, flexure, compression, and impact properties have been evaluated). Insulation performance can be further enhanced by decreasing the channel diameter from micro- to nano-scale, which constrains gas conduction by the Knudsen effect, while reinforcement of the epoxy matrix with lightweight fiber veil allows for a variety of composite configurations to be achieved which demonstrate the robust mechanical properties required for space habitat materials.