Green Reinforcement of Epoxy Nanocomposites: Enhancing Flame Retardancy and Mechanical Properties with Epoxidized Linseed Oil, MWCNTs, and Montmorillonite Clay

Abstract

This study focuses on enhancing the flame retardancy and mechanical properties of epoxy nanocomposites by incorporating multi-walled carbon nanotubes (MWCNTs), montmorillonite nanoclay I.30E, and flame retardants such as chlorinated paraffin and antimony trioxide. The materials were fabricated through mechanical stirring and ultrasonication, ensuring uniform dispersion of additives within the epoxy matrix. The results indicate that the optimal ultrasonication time for dispersing MWCNTs is 90 min at room temperature, with 0.10 wt% MWCNTs significantly improving mechanical properties and flame retardancy. The addition of MWCNTs and nanoclay I.30E increased the limiting oxygen index (LOI), reduced the combustion rate, and formed a protective layer that prevented flame propagation. When 2 wt% nanoclay was added, tensile strength increased to 72.17 MPa, flexural strength reached 133.34 MPa, and compressive strength improved to 200.26 MPa. However, at higher concentrations (3-4 wt%), mechanical properties deteriorated due to uneven dispersion. Additionally, epoxidized linseed oil (ELO) was used as a plasticizer to enhance flexibility and optimize the balance between mechanical performance and flame retardancy. The MWCNTs/Nanoclay I.30E/Sb2O3/CP system with 10 wt% ELO achieved the highest LOI (36.4 %), the lowest combustion rate (5.58 mm/min), and a UL-94 V-0 rating. Overall, this study demonstrates that the combination of MWCNTs, nanoclay I.30E, flame retardants, and glass fibers significantly improves the mechanical and flame-retardant properties of epoxy composites, making them suitable for high-safety applications in various industries.