Phytolith-derived 2D nano-SiO ₂ /PMMA composites: Preparation and properties

A naturally occurring two-dimensional (2D) nano-SiO 2 derived from phytolith minerals was employed as a reinforcing filler for polymethyl methacrylate (PMMA) composites. Unlike conventional 2D materials, this SiO 2 does not require exfoliation, significantly reducing processing complexity and cost. The nanosheets were modified using 3-aminopropyltriethoxysilane (KH-550) and incorporated into PMMA via melt blending. FTIR analysis indicated that the 2D nano-SiO 2 was successfully modified by KH-550 and effectively grafted onto the PMMA chains, while SEM analysis revealed a distinct layered structure and strong interfacial adhesion, contributing to a porous morphology. Mechanical tests demonstrated that at an optimal loading of 1.06 wt.%, the composite achieved a tensile strength of 72.74 MPa and an impact toughness of 70.23 kJ/m 2 , representing increases of approximately 93.8% and 100.6% compared to pure PMMA. DSC analysis showed a slight increase in the glass transition temperature, indicating modest enhancement in thermal stability. These findings suggest that natural 2D nano-SiO 2 serves as a low-cost filler with a remarkable reinforcing effect on the mechanical performance of PMMA-based composites, exhibiting great potential for engineering applications.