Investigation of the impact of multi-walled carbon nanotubes on the properties of pvoh-corn starch composites system

Lean, Xin Hui (2026) Investigation of the impact of multi-walled carbon nanotubes on the properties of pvoh-corn starch composites system. Final Year Project, UTAR.

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Abstract

This study investigates the effects of multi-walled carbon nanotubes (MWCNTs) on the mechanical, structural, and antioxidant properties of polyvinyl alcohol (PVOH)–corn starch composite films for sustainable food packaging applications. Using a solution casting method, 9 formulations with a 75:25 PVOH-to-starch base ratio were produced by varying the MWCNT loading (0.1g to 0.3g) and Tween 20 surfactant ratios (1.0:1 to 2.0:1). A wide range of characterization tests, such as mechanical testing (tensile strength, Young's modulus, and elongation at break), scanning electron microscopy (SEM) for morphological analysis, Fourier transform infrared spectroscopy (FTIR) for chemical interaction tracking, X-ray diffraction (XRD) for crystallinity assessment, and the DPPH Scavenging Activity Assay for antioxidant potential, were used to assess the effect of nanofiller dispersion on the matrix. Mechanical tests showed a major trade-off. At higher concentrations, MWCNT loading simultaneously caused brittleness and reduced tensile strength even though it greatly increased stiffness, peaking at a Young's modulus of 527.78 MPa. Formulation 9 (0.3g MWCNT, 2.0:1 surfactant ratio) achieved the best crystalline perfection with a maximum lateral crystal size of 0.82 Å and a uniform, defect-free surface according to structural analysis using XRD and SEM. The 2.0:1 surfactant-to-nanotube ratio was crucial for enhancing molecular integration through improved hydrogen bonding according to FTIR measurements. Furthermore, this ideal ratio produced a high antioxidant activity of 6.073% by maximizing the nanotubes' ability to scavenge radicals. Although MWCNTs significantly reinforce the composite while offering sufficient functionality, the 2.0:1 surfactant ratio is essential to prevent agglomeration and structural defects. Future research should look into higher surfactant ratios and useful shelf-life testing to further enhance material performance for active packaging. Keywords: Polyvinyl alcohol (PVOH), Corn Starch, Multi-walled carbon nanotubes (MWCNTs), Solution Casting, Tween 20, Mechanical Properties, SEM, FTIR, XRD, DPPH Antioxidant Assay.

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