Development of Multifunctional Film for Greenhouse Applications in Tropical Regions

A Petchsuk,D Srinun,W Supmak,S Buchatip,D Sirikittikul

doi:10.1155/2019/1692126

Abstract

Single-purpose greenhouse films such as UV-blocking, NIR-blocking, or ultrathermic films are commonly developed in various climate regions. However, multifunctional films of combined functions are rarely explored, especially in the tropical regions. In this research, a multifunctional film having high UV filtration, high NIR reflection, and good light diffusion was developed for a greenhouse cover application in tropical regions. Effects of type, quantity, and particle size of additives on optical properties (280–2500 nm) and mechanical properties of 3-layer laminated films comprising 90% LLDPE/10% EVA polymer matrix and additives were studied. Results show that properties of those films are adjustable by varying types, particle size, and content of additives. The UV transmission of the film was ranged from 13.7 to 32.7 %T, NIR reflection from 12.1 to 19.8 %R, and %haze diffusion from 39.5 to 72.3 where photosynthetically active radiation (PAR) transmission was in the range of 62.6–78.9 %T. Those films exhibit tensile strength of 18–24 MPa, modulus of elasticity of 200–280 MPa, and elongation at break of 610–810%. A field test of the newly developed films as a cover for a greenhouse of 6 m wide ×24 m long ×4.3 m high with double roof design showed a better quality of plant growth in terms of weight, height, and bush width compared to a 7% UV absorber commercial film.

Highlights

Greenhouse films of a single function such as ultrathermic, UV-blocking films have been extensively developed, especially in the cold climates
Field Test. e newly developed films of two selected formulas were industrial blown into three layers of 120 μm total thickness for a field test. e greenhouse of 6 m wide ×24 m long ×4.3 m high with double roof design was covered with the obtained films compared with a 7% UV absorber
It should be noted that the observed FTIR and 13C NMR spectra of the modified UV2 were resembled to that of the modified UV1. e UV1 additive after modification was found to locate more in the hexane layer than in the DI water layer implying the increase of the hydrophobicity of the modified additive, as seen in Figures 3(a) and 3(b)

Summary

Introduction

Greenhouse films of a single function such as ultrathermic, UV-blocking films have been extensively developed, especially in the cold climates. Other NIR absorption/reflective materials that have been developed for greenhouse cover include black iron oxide, blue cobalt oxide, coated copper powder, lanthanum hexaboride, and metal compounds such as CoAl, NiSbTi, CrSbTi, CoNiZnTi, and MnSbTi. ose films could reduce the UV transmission to 42–53% and reflect NIR radiation by 8–14%. E light diffusion is another important property of the greenhouse cover aside from high PAR transmission, NIR reflection, and UV filtration. Erefore, it is a challenge to develop a new generation of covering materials that have multiple functionalities including UV filtration, NIR reflection, and light diffusion in a single film. To achieve all these requirements, the multifunctional film with the combined additives of UV absorber and NIR-reflecting material was prepared in this study. Studies on plant growth and air temperature inside the greenhouse were compared to a commercial film

Experimental

Results and Discussion

Conclusions