Tensile, flexure, and compression properties of anisotropic microchannel epoxy foams

ABSTRACT Microvascular architectures with specific channel fractions and channel orientations have been reported for thermal insulation and functional fluid delivery applications. However, the dependence on channel network structure of the inevitable loss in strength and stiffness has not been adequately characterized, especially at moderate‐to‐high channel fractions and in anisotropic systems. In this work, the loss in mechanical performance of a thermosetting epoxy is explored in tensile, flexure, and compression modes over a wide range of microchannel fractions and different microchannel orientations. Whereas microchannel fractions of 0.7 can result in reductions of more than 90% in mechanical properties relative to the nonchanneled material, there is a strong influence in microchannel orientation over the full range of microchannel fractions studied. The data are compared to a power‐law model, which shows a good agreement with the experimental measurements, provided that the power‐law exponent is adjusted to depend on the direction of microchannel alignment. These results demonstrate the opportunity to engineer the mechanical properties of multifunctional microchannel systems for a range of existing and emerging applications, by controlling both the microchannel volume fraction and the microchannel orientation. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47945.