Fabrication of graphene and graphene derivatives based thermoplastic nanocomposite films for high barrier antibacterial packaging, EMI shielding and thermal management applications

Abstract

Multifunctional polymer/graphene nanocomposite based lightweight and flexible films are increasingly being utilized in the packaging, electronics, and pharmaceutical industries together. Herein, three different types of graphene derivatives have been incorporated into linear low density polyethylene (LLDPE) thermoplastic matrix via melt compounding method. As an anisotropic filler that is extensively employed, graphene possesses the ability to not only impose electrical conductivity, but also increase their barrier properties and reinforcement to a larger extent. The microscopic analyses showed that, because of polarity, graphene nanoplatelets are the most significant and accepted filler for homogeneous mixing in the LLDPE matrix. But in order to fabricate a versatile sub-millimeter packaging film, noble metal has been deposited onto the graphene sheets (G-Ag) via wet chemical synthesis method followed by melt mixing with LLDPE matrix. This modification affected the electrical conductivity, barrier properties (both oxygen and water vapor permeability), and UV-transmittance. With 5 wt% of G-Ag, reduced graphene oxide (RGO), and graphene nanoplatelet (GNP) loading, the thermal conductivity of these three nanocomposite films was enhanced by an average of 82%, 77%, and 96%, respectively. Moreover, the film has been tested against both gram-positive and gram-negative bacteria to ensure its bactericidal activity. The prepared graphene derivatives reinforced thin films were also showing EMI shielding values (-21 dB, -17 dB, and -19 dB) more than the commercial cut-offs. Therefore, it is possible to deduce graphene-based thermoplastic nanocomposite, which might be an excellent choice for bacteria-resistant and barrier-capable packaging and efficient thermal management EMI shields in wearable and flexible electronics.