Investigating the viscoelastic properties and curing kinetics of thermoset nanocomposites via dynamic shear rheological analysis

Abstract

Mechanical properties of a thermosetting composite can be theoretically determined by using its physical and chemical characteristics, and these properties are also immensely influenced by the viscoelastic structures and curing stages of the material throughout the curing process. This study explores the process conduct and curing kinetics of a commercial thermosetting epoxy resin, Loctite EA 9394 Aero. The material characteristics are calibrated on a constant isothermal cure profile using different weight percentages of nano-filler inclusions in the shear rheometry. For the LoctiteEA9394 Aero nanocomposites, it is inferred that addition of different percentages (0%, 1%, 2%, 4%) of nanoparticles (e.g., carbon black and zeolite) significantly alters the advancements in the cure chemical reactions towards the isothermal cure temperature (Tcure=93℃). The changes were noticed in the values of shear and storage modules, and tanδ where the carbon black nanocomposites exhibit elastic and viscous properties at the same time under thermal alteration / deformation. It also indicates that the material carries an excellent dampening coefficient. Besides, the zeolite nanocomposites reveal more of elastic solid and less viscous simultaneously under deformation providing the moderate dampening effect. The existence of nanoparticles among the polymer chains modifies the flow-ability of the resin molecules across the cure reaction, prompting vitrification process.