High-performance thermosetting resins, such as benzoxazine and epoxy, have been intensively used in aerospace and defense industries due to several advantages that these resins provide; these consist of high mechanical performance, good thermal and chemical resistance, ease of manufacturing, and compatibility with several types of filler incorporation.

Alloying bisphenol-A based benzoxazine (BZ-a) with cycloaliphatic epoxy (CER) resins was found to combine the advantages of each component together. The composition of BZ-a/CER copolymer processed high glass-transition temperature (T_g), high crosslinked density, and low viscosity, which was suitable for an advanced composite fabrication like a resin infusion method. However, the mechanical performances of the copolymer were observed to deteriorate with the addition of CER compared to the neat BZ-a matrix.

The objective of this study was therefore to incorporate two-dimensional graphene nanoparticles (GNPs) into the BZ-a/CER copolymer matrix to enhance its mechanical performance and electrical conductivity for application in advanced composite manufacturing. The addition of GNPs was performed at various loading ratios, ranging from 0.3 to 3.0 wt.%, where two different particle dispersion methods were performed, (a) ultrasonication; and (b) three-roll mill (3RM) calendering. The effects of mixing process parameters, specifically different ultrasonication durations and mixing speeds, were analyzed to determine nanoparticle dispersion quality.

The results of this new method showed a statistically significant improvement in mechanical and electrical properties. These enhancements, moreover, introduce a path to manufacture high strength to weight ratio, high thermal-performance, and conductive materials, which are better suitable to industries such as aerospace, automotive, and electronics.