Rapid forming of programmable shaped morphogenic composite through additive manufacturing & frontal polymerization

Abstract

Compared to thermoplastics, continuous fiber thermosets offer the potential for diverse reaction chemistry, improved thermo-mechanical properties, and new processing routes. In this work, flat preforms of additively deposited reactive resin infused fiber tows (ADRRIFT) are combined with frontally polymerizable gels of dicyclopentadiene (DCPD) to autonomously produce, upon initiation of frontal polymerization (FP), cured composites with controlled curvature. These morphogenic composites provide a low initiation energy ($\approx$10–20 J) and rapid ($\approx 70{\mathrm{cm}}^2$/$\min$) method to form 3D shaped composites. Using an analytical model, 2D printed patterns of continuous carbon fiber tows are designed to produce shapes with an apparent Gaussian curvature that is positive (parabolic dish), zero (cone), and negative (saddle). To achieve the strain needed for desired shapes, these morphogenic composites have low fiber volume fraction (FVF), 3%–9%. However, we also demonstrate in this work that the shaped morphogenic composites can serve as rapid tooling for DCPD infused laminates with higher FVF (30%–42%) and mechanical stiffness. Due to the inherent surface chemistry, cured laminates easily separate from the shaped tooling without additional release agents. Together these approaches provide rapid manufacturing of shaped composites with a range of FVF and properties for application constrained in transportation volume and energy expenditure.