Mechanical properties of carbon nanotubes/epoxy nanocomposites: Pre-curing, curing temperature, and cooling rate

The effects of composite fabrication, such as pre-curing, curing temperature, and cooling rate, were studied. In this work, the pre-curing was defined as heat treatment of Multi-Walled Carbon Nanotubes (MWNCTs) with Diglycidyl Ether of Bisphenol A (DGEBA) epoxy resin. Acid purified MWCNTs were characterized by Raman spectroscopy and Fourier Transform Infrared Spectroscopy (FTIR). The pre-curing facilitated bonding between MWCNTs and epoxy via the oxirane ring of DGEBA, which accelerated the curing process of epoxy and increased mechanical properties. The elevated curing temperature on the pre-cured sample further improved the composite's mechanical properties by increasing interfacial bonding due to cross-linking. The rapid cooling using liquid nitrogen during pre-curing treatment prevented re-agglomeration of MWCNTs, showing smaller agglomerates and improving the mechanical properties. Agglomeration was characterized by scanning electron microscopy, while the bonding between MWCNTs and epoxy was examined by the length of fibre pull-out on the fracture surface. Tensile testing was deployed for mechanical properties characterization. The degree of cure was determined by FTIR and Differential Thermal Analysis (DTA).

Automated summary

This study investigated the effects of composite fabrication, such as pre-curing, curing temperature, and cooling rate, on the mechanical properties of Multi-Walled Carbon Nanotubes (MWCNTs) and epoxy resin composites. Pre-curing improved bonding between MWCNTs and epoxy, while elevated curing temperature and rapid cooling further enhanced mechanical properties through increased interfacial bonding and prevention of re-agglomeration of MWCNTs. Characterization techniques such as Raman spectroscopy, Fourier Transform Infrared Spectroscopy, and scanning electron microscopy were employed to study the bonding between MWCNTs and epoxy, as well as the agglomeration of MWCNTs. Tensile testing, FTIR, and Differential Thermal Analysis were used for mechanical properties characterization and degree of cure determination.