Nanocomposite films with enhanced radiometric properties for greenhouse covering applications

Abstract

Nanocomposite films for covering applications were developed. Mechanical, radiometric and ultraviolet stability properties of the films were characterized. Nanocomposites were obtained by incorporating nanoadditives to a thermoplastic polymer matrix by melt-mixing in a corotating twin screw extruder. Three common polymers in cover applications were used as matrix: low-density polyethylene, linear low-density polyethylene and ethylene-butyl acrylate. Three different nanoparticles were used as fillers (2 wt%): titanium dioxide (rutile), silicon oxide and zinc oxide. All nanocomposites were processed in a blown film extrusion line, producing 200 mm thick films. The mechanical properties of the nanocomposite films were found to be slightly different than those of the neat films, whereby the optical and radiothermal properties changed dramatically. Titania nanocomposite containing films had high ultraviolet shielding, however, significantly reduced transparency. Zinc oxide introduced high ultraviolet-shielding capability preserving transparency. High infrared efficiency has been found in silica nanocomposite films, exhibiting efficiency values greater than 79%, and an increment greater than 100% for linear low-density polyethylene and low-density polyethylene nanocomposite films. The extent of ultraviolet degradation of the films was determined by elongation at break tests. Zinc oxide/low-density polyethylene Downloaded from film underwent less degradation than neat low-density polyethylene film after photoaging. Thus, zinc oxide-filled polymer nanocomposite films are suitable for transparent ultraviolet-shielding applications and present low degradation rates. Silica incorporation highly improves polyethylene infrared efficiency, rendering a low-cost high-thermicity transparent film.

Influence of TiO2Nanoparticle Filler on the Properties of PET and PLA Nanocomposites

“…These nanofillers caused a considerable visible transmission loss in the films, so that the visible transmission at 500 nm wavelengths diminished from above 80% to below 20% in PET nanocomposites, and from above 20% to below 15% in PLA nanocomposite films. Espejo et al (2012) observed that incorporation of 2 wt% of TiO 2 , SiO x and ZnO nanoparticles reduced the visible transmission of LDPE films from 86.5% to 32.7, 83.25 and 75.18%, respectively. 27 The maximum UV-transmission loss was also observed with TiO 2 nanoparticles compared to SiO x and ZnO fillers.…”

“…Espejo et al (2012) observed that incorporation of 2 wt% of TiO 2 , SiO x and ZnO nanoparticles reduced the visible transmission of LDPE films from 86.5% to 32.7, 83.25 and 75.18%, respectively. 27 The maximum UV-transmission loss was also observed with TiO 2 nanoparticles compared to SiO x and ZnO fillers. Sunay et al (2012) observed that the trans- …”

Red photoluminescent PMMA nanohybrid films for modifying the spectral distribution of solar radiation inside greenhouses

“…11, it is observed that the photoselective films had a significant peak of reflectivity around 650 nm which is associated with the wavelength absorbed by chlorophylls. This property will introduce a direct influence on plant growth; especially for LSC films doped with ZnO and TiO 2 nanoparticles which can diffuse light more efficiently than the others [56]. Fig.…”

The Feasibility of Rice Bags and Ground Tarp Plastics as Low-Cost and Locally-Available Alternatives to Greenhouse Glazing

“…8, No. 6;2015 resulting weight of the coating, which uses a polyethylene base as its matrix (Espejo, et al 2012). Altogether the substances form a coating about 200 microns thick.…”

“…Titanium based films are much less transparent, but excel at protecting the greenhouse from UV damage. The zinc based film preserves the transparency of the original material, while still blocking a significant amount of UV decay, making them optimal for use with greenhouse glazing (Espejo, et al 2012). Another coating that can be applied to glazing materials is an anti-drip layer.…”