MWCNTs polymer nanocomposite with enhanced thermomechanical properties and electrical insulation for effective encapsulation

This study presents the effect of the variation in weight fraction of multiwall carbon nanotubes (MWCNTs) in polymer with the objective of enhancing the thermo-mechanical properties along with the electrical insulating properties. Polymer multi-walled nanocomposites (PMWCNC) and MWCNTs/Al2O3 bi-layer nanocomposites were prepared by solution mixing method with ultrasonication and magnetic stirring, then molded in vertical sandwich molds, made of acrylic and aluminum sheet as per ASTM standards. The tensile strength of PMWCNC was enhanced by 32%, 23%, 15%, and 5% compared to unmodified epoxy with the incorporation of 1 wt%, 0.75 wt%, 0.5 wt%, and 0.25 wt% of MWCNTs. The dispersion morphology of MWCNTs in epoxy was observed with field emission-scanning electron microscope (FE-SEM). The thermogravimetric analyzer (TGA) investigation found that increasing the weight percentage of MWCNTs resulted in improved thermal stability. The enhanced electrical conductivity of PMWCNC caused by the addition of MWCNTs was countered through the deposition of a thin film layer of alumina-filled polymer nanocomposite on the top surface of PMWCNC to retain the electrical insulation properties. The representative volume element (RVE) technique was employed to predict the effective modulus of nanocomposite based on the various constituent properties, weight fractions and interfacial behavior between MWCNTs and epoxy with the help of finite element analysis. Additionally, Modified Mori-Tanaka (MMT) micromechanics scheme was used to find the effective elastic modulus of the nanocomposite with the help of the MATLAB code. The elastoplastic behavior of polymer nanocomposites was also simulated in ANSYS APDL through the Voce model. The enhanced thermomechanical properties while retaining the electrical insulation properties suggest that the MWCNTs-based polymer would make the electronic chip more reliable.