Dynamic Mechanical Properties of Carbon Fiber Reinforced With Macropore-Infused Nanoparticle Emulsion Thermoset (MINETs)
Authors: Mohanty Rituparna , Patel Yogin , Llumiquinga Bryan , Singer Jonathan P. 
Published: August 2024

Macropore-infused nanocomposite emulsion thermosets (MINETs) represent an innovative category of nanocomposite materials synthesized using common industrial constituents such as epoxy resin, nanoparticles, a liquid porogen, and surfactant. They are prepared by creating a microphase separation of two immiscible phases (here being the polymeric resin and non-volatile oil) stabilized by a surfactant and jammed with a nanoparticle or particle blend by employing high shear mixing. Following ambient temperature curing and optional oil phase extraction through rinsing results in MINETs having open porosity at tunable length scales that can be infiltrated with selected working fluids to achieve the desired function. Optimizing the composition of MINETs facilitates the introduction of multifunctionality into the composites. This tailoring for multifunctionality involves incorporating various functional nanoparticles selected based on their application requirements. Notably, the size of the resulting pores is influenced by the choice of nanoparticles. Altogether, the function of MINET can be optimized depending on the choice and composition of the nanoparticle(s), the choice of the filler fluid, the choice of the polymeric resin, and the choice of the surfactant. The primary objective of this investigation is to affirm the viability of MINETs as a resin matrix alternative in carbon fiber composites while maintaining the mechanical resilience characteristic of traditional carbon fiber composites (CFCs). The study focuses on the incorporation of MINETs into carbon fiber composites (CFCs) and assessing the dynamic mechanical properties of the resultant structures, together with the associated challenges encountered during this process. Optimizing the MINET composition enables multifunctionality but requires an understanding of each constituent’s interaction with carbon fibers. For instance, a notable setback surfaced when attempting to integrate silica-based MINETs into the carbon fiber matrix. This endeavor yielded composites exhibiting poor mechanical properties and delamination. To mitigate these issues, carbonaceous nanoparticles were introduced into the MINET composition. The shift from silica to carbonaceous nanoparticles improved the mechanical properties of the MINET carbon fiber composite, thus highlighting the importance of the particle carbon fiber compatibility. Employing graphene as the nanoparticle of choice yielded MINETs with expected higher electrical and thermal conductivity but compromised the mechanical properties of the resulting carbon fiber composites. Subsequently, the replacement of graphene with graphite was explored, which contributed to the enhancement of mechanical properties. Nevertheless, this substitution came with repercussions, as it affected the porosity and conductivity of the MINET carbon fiber composites. The blending of graphite and graphene bore intermediate results allowing for co-optimization of the mechanical and electrical properties. However, these findings require further optimization and investigation to be termed as quantifiable components for toughening mechanisms. Ultimately, this research opens the door to a novel platform capable of integrating multifunctionality into forthcoming aerospace structures.