Effects of alternative jet fuel blends on aerospace-grade carbon/epoxy composites. (September 2022) - Harich, Naoufal
Graphical abstract: Highlights: Carbon/Epoxy composites with different material systems and layups were immersed in conventional Jet A fuel and four alternative fuel blends. Similar fuel uptake rates and equilibrium weight gains occurred for all fuels in each composite type. Specimens with different ply layups of the same material system did not show differences in equilibrium fuel uptake. Different fiber packing influenced fuel uptake as composites with woven fabric absorbed more than warp-knitted ones. Tg decreased by 1.8–20.6 °C at saturation for all five fuels considered here. Abstract: The effects of Jet A fuel and four alternative fuel blends on different carbon/epoxy composites were investigated. The alternative fuel blends consisted of 50/50 or 90/10 vol% blends of Jet A fuel with low aromatic content non-petroleum sourced fuels. These alternative fuel blends had previously passed the Federal Aviation Administration (FAA) certification process as drop-in fuels with the aim of reducing the environmental imprint of conventional jet fuels. The time-dependent absorption behavior of Jet A and these alternative fuel blends into three different types of carbon/epoxy composites were studied, and no significant differences in fuel absorption were observed for different fuels for a similar composite. The fuel uptakes were low for all three composites, varying from 0.04 to 0.36 wt%. However, the arrangement of fiber tows and individual filaments within plies appeared to affect fuel uptake. Additionally, the effects of the absorption of all five fuels on the composites' glass transition temperature ( Tg ) were investigated. The composite Tg values decreased in the range of 3.1–19 °C for Tg and 1.8–20.6 °C for Tt for all specimens after fuel absorption. The alternative fuel blends exhibited similar results to that of Jet A for equilibrium fuel uptake amounts, uptake rates, and effects on the composites' Tg .