Graphene quantum dots/cellulose nanocrystal inclusion complex for enhancing the physical and thermal properties of HDPE polymer matrix

Abstract

Cellulose nanocrystals (CNC) are desirable material due to universal accessibility, and superior mechanical properties. A major challenge is non-uniform dispersion of CNC in the hydrophobic matrices due to their tendency to agglomerate. A novel technique was evaluated to prepare a hybrid system of cellulose nanocrystal (CNC)/graphene quantum dots (GQD). Hybrid system of CNC/GQD was added to high density poly (ethylene) (HDPE) to manufacture composites. The CNC/GQD inclusion complex properties were evaluated using Zeta potential measurement, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analysis. The composite properties were analysed using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and tensile testing and analysis of electrical impedance spectra. Raman spectroscopy, XPS and XRD confirmed the interaction of CNC and GQD. The SEM micrographs of the cross-sections of GQD induced composites showed a uniform honeycomb like morphology and no sign of agglomeration. GQD incorporated composites exhibited better thermal stability and higher elastic modulus than neat HDPE. The composites showed a purely capacitive response for an AC electrical system measured over 4 Hz to 1 MHz. The results indicate significantly improved dispersion of CNC in the polymer matrix, compared to unmodified CNCs.

Keywords

• Cellulose nanocrystal
• High-density poly(ethylene)
• Graphene quantum dots
• Inclusion complex
• Bio-based nanofillers