Improved rheological, barrier, antibacterial, and electromagnetic interference shielding properties of graphene and graphene derivatives based linear low density polyethylene nanocomposites

Multifunctional polymer/graphene based lightweight and flexible nanocomposite films are increasingly being utilized in the packaging, electronics, and pharmaceutical industries together. Herein, two graphene derivatives: silver nanoparticle decorated reduced graphene oxide (G-Ag) and chemically reduced graphene oxide (rGO) prepared by wet chemical method and graphene nanoplatelets (GNP) have been incorporated into linear low density polyethylene (LLDPE) thermoplastic matrix via melt compounding method. The incorporation of graphene derivatives affected the physico-mechanical, electrical and thermal conductivity, and barrier properties (both oxygen and water vapor permeability) of the nanocomposite films. With 5 wt% of G-Ag, rGO, and GNP loading, the thermal conductivity of these three nanocomposite films was enhanced by an average of 136.7%, 123%, and 143.3%, respectively. Graphene having high specific surface area and aspect ratio allow for a tortuous passage of oxygen and water molecules through the nanocomposite film, ultimately improving both oxygen and water vapor impermeability qualities for all LG-Ag, LrGO, and LGNP nanocomposites. Moreover, the films have been tested against both gram-positive and gram-negative bacteria to ensure their bactericidal activity. The prepared composite films also showed Electromagnetic Interference (EMI) shielding effectiveness (-21, -17, and -19 dB) higher than the commercial cut-offs. The thermoplastic nanocomposite films with promising thermal conductivity might be an excellent choice for bacteria-resistant and barrier-capable packaging and efficient thermal management EMI shields in electronics.