INFLUENCE OF NANO-SIO2/POLYAMIDE COMPOSITES COATING ON THERMIC EFFECT AND OPTICAL PROPERTIES OF POLYETHYLENE FILM

Polyethylene (PE) film was coated with nanosilica-polyamide layer using rod Mayer process. The nanosilica-polyamide system was prepared by dispersing nanosilica (nano-SiO2) powder into solvent borne polyamide binder under vigorous stirring. Various compositions of nanosilica-polyamide slurry were prepared. The thickness of the layer was about four mu m and eight mu m for single and double layer coating respectively. A battery of characterization procedures were used to study the properties of the nanocomposite coating. The uniformity of silica dispersion was probed using elemental mapping procedure and scanning electron microscopy (SEM). With the introduction of nanosilica to polyamide binder, the visible light transmittance and ultra-violet (UV) radiation of nanosilica-polyamide system reduced with increasing nanosilica content and coating layer thickness. Infrared (IR) effectiveness (between 7 mu m to 13 mu m wavelengths) measurements by FTIR also showed that nanosilica-polyamide system coating on PE film surface greatly improved the thermic effect of PE film. The nanocomposite coating containing 14 wt% nanosilica and with eight mu m coating thickness has improved the IR effectiveness of PE to 76%. Thermic effect of the nanocomposite increased with increasing nanosilica content and coating thickness.