Effect of cellulose nanocrystals and carbon nanotube as hybrid nanofillers on poly (vinyl alcohol)/cellulose nanocrystals/carbon nanotube nanocomposites

Scientists and engineers have been fascinated with polymer nanocomposite materials over the past two decades because of the improved characteristics gained by using nanoscale fillers. A hybrid filler of cellulose nanocrystals and carbon nanotube (CNC/CNT) made up of two or more filler materials with various dimensionalities can have a robust synergistic impact, outperform individual fillers, and improve the performance of nanocomposites to their full potential. It can also be used in electronic sensor products.
In this research, hybrid nanofillers of cellulose nanocrystals (CNC) and carbon nanotubes (CNT) were mixed with polyvinyl alcohol (PVA) to produce CNC/CNT/PVA nanocomposites. Five samples of hybrid nanofillers were prepared by mixing 0.4g, 2.5g, 4.6g, 6.8g and 9.2g of carbon nanotubes (CNT) and 6 wt. % of cellulose nanocrystals (CNC) together with the amount of material for the preparation which is as follows; 0.2 g/49.8 g, 1.2 g/48.8 g, 2.2 g/47.8 g, 3.2 g/46.8 g, and 4.2 g/45.8 g was labelled 0.4 wt.% of CNT/CNC, 2.5 wt.% of CNT/CNC, 4.6 wt.% of CNT/CNC, 6.8 wt.% of CNT/CNC and 9.2 wt.% of CNT/CNC respectively. Then, the hybrid nanofillers were added to the PVA solution to form CNC/CNT/PVA nanocomposite. The prepared CNC/CNT hybrid nanofillers were characterised for stability test, fourier infrared spectroscopy - attenuated total reflectance (FTIR-ATR), scanning electron microscopy (SEM) and viscometer.
Morphology and physicochemical analysis of the prepared CNC/CNT/PVA nanocomposites were characterised using Field-Emission Scanning Electron Microscopy
(FESEM), fourier infrared spectroscopy - attenuated total reflectance (FTIR-ATR), and X-ray diffraction (XRD). The thermal stability, melting, and crystallization behaviours of (CNC/CNT/PVA) nanocomposites were investigated using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Mechanical properties of (CNC/CNT/PVA) nanocomposites were studied using universal tensile testing machine (UTM) for tensile tests. The stability of CNC/CNT was observed and it was found that the solution could remain in one phase until the sixth month. The viscosity of the samples showed that 4.2g CNT/CNC hybrid nanofiller had a high viscosity with 191.33 cP. X-ray diffraction (XRD) exposed the sample was low crystallinity. The surface roughness of CNC/CNT/PVA analysis using FESEM showed that the 3.2 g CNC/CNT/PVA had the highest surface roughness compared to other samples. The tensile test showed that the sample 3.2 g CNT/CNC had the highest ultimate tensile strength of 67.444 MPa, compared to 4.2 g CNT/CNC with a tensile strength of 21.643 MPa. Both TGA and DSC results indicated that the thermal stability of CNC/CNT/PVA nanocomposite increased due to the high content of CNT in the nanocomposite. By combining existing nanomaterials and fabricating hybrid nanofillers and incorporating them into a polymer, researchers can create new multifunctional nanocomposites.