**Abstract**

This work represents the results of experiments on silicon dioxide insulation materials mixed with low-density polyethylene (LDPE) at a different proportion to prevent the transmittance of IR domain and to allow the transmittance of ultraviolet–visible (UV–Vis) domains, so we can keep the thermal radiation of the ground in the greenhouse. The mechanical properties of nanocomposites such as tensile were evaluated and discussed. Several ratios of nanosilica particles were employed to fabricate low-density polyethylene (LDPE) composites using melt mixing and hot molding methods. Six of composite films from different ratios (0.5, 1, 2.5, 5, 7.5, and 10 wt% nanosilica) were prepared. The obtained composite films were characterized and identified by ultraviolet–visible (UV–Vis) spectroscopy and Fourier transform infrared spectroscopy (FTIR). Thermal stability of samples was evaluated by thermogravimetric analysis (TGA). Surface morphology of samples was investigated by scanning electron microscopy (SEM). At specific mixing ratio, the ultraviolet–visible transmittance is allowed, while far infrared radiation transmittance was prohibited, and that will be explained in details. Optical measurements show that the composite films prevent the transmission of IR radiation near 9 μm and allow UV–Vis transmission during sun-shining time. The mechanical behavior was studied using tensile tests for nanosilica-reinforced LDPE composite. The sample with an addition of 1 wt% nanosilica has successfully enhanced the mechanical properties of LDPE material.

**Keywords:** silicon dioxide (SiO2), low-density polyethylene (LDPE), composite barrier films, Fourier transform infrared spectroscopy (FTIR)
