DICYCLOPENTADIENE-EPOXY BLENDS FOR LOW-ENERGY PROCESSING OF TOUGHENED CARBON FIBER COMPOSITES

In-space composite manufacturing is a growing field that uses carbon fiber reinforced composites to expand design possibilities for in-space structures. Traditional composites have historically been limited to time- and energy- expensive epoxy composites bulk cured in large autoclaves and subsequently sent to space. Frontal ring opening metathesis polymerization (FROMP) of dicyclopentadiene (DCPD) has been examined as a more efficient method of in-space manufacturing. We seek to balance the properties of these high-performance thermosets for in-space manufacturing to find a resin blend that exhibits synergistic properties while maintaining an efficient cure applicable for in-space manufacturing. In this study, EPON 826 and nadic methyl anhydride (NMA) were added to dicyclopentadiene monomer and Grubbs 2nd catalyst (GC2) to create a poly-dicyclopentadiene (DCPD) and epoxy (EP) copolymer mixture. The properties of the resulting formulations were analyzed to determine a fast and energy efficient curing procedure that would result in a compatible system for composite manufacturing in space. The viscosity and volatility of the liquid resin, as well as the thermal stability and compatibility of the mixtures upon cure, were studied. It was found that using DCPD as the primary phase, the hybrid system has a low enough viscosity to be vacuum infused into composite panels. Thermomechanical testing of neat resin was used to down select to a specific range of DCPD-rich resin blends. With a specific formulation mixture chosen, the effects of sequential reaction of components by pre-gelling and novel cure schedules were explored. Composite panels were prototyped, and a through-thickness cure cycle was developed. The resulting cure cycle yields a synergistic resin blend resembling an