Tunable structural, thermal and colloidal properties of anionic cellulose nanocrystals from oil palm biomass/metal oxide nanoparticles hybrid nanocomposites.

Cellulose nanocellulose (CNPs) is a virtual inexhaustible source of feedstock meeting the increasing demand for green, biocompatible products and ideal candidates for nanocomposites preparation for various application such as in packaging, biomedical devices, electronics, water treatment, energy storage devices and also in electronics application. However, integration of CNPs based nanocomposite into nanofluid application has received little attention which presents a clear research gap. As a result, this study used a bio-based functionalized sodium carboxymethyl nanocellulose (ACNPs) synthesis from oil palm empty fruit bunch (OPEFB) as a template, to synthesize hybrid nanocomposites with metal oxide (MONPs) at varying ACNP-to-MONP weight ratio. The present of COO groups on the ACNPs act as template for coordinating metal precursors, promoting uniform MONP growth and strong interaction with ACNPs. Characterization techniques such as Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and field emission scanning electron microscopy (FESEM) confirm the successful formation of MONPs on ACNPs by examine the morphology, distribution, chemical states, and bonding environments of the MONPs on the ACNPs. Besides this, thermogravimetric analysis (TGA) and zeta potential characterization are also conducted to assess the thermal and colloidal stability of the produced hybrid nanocomposites. Based on the result, hybrid nanocomposite with 1:1 weight ratio of ACNPs to MONPs was selected as an optimized weight ratio. In order to evaluate the performance and efficiency of the produced hybrid nanocomposite in nanofluid, thermal conductivity test was conducted using KD2Probe. The result indicating that the utilization of ACNPs as template for nanocomposite synthesis leads to a significant optimum enhancement in the thermal conductivity at temperature 45 °C, improving it by approximately 129, 100, 80 and 56 % after adding ACNPs/AlO, ACNPs/ZnO, ACNPs TiO and ACNPs/MgO based hybrid nanocomposite which making it a promising candidate for water based-heat transfer application.