Greenhouse plastic films are subjected to degradation due to their exposure to solar radiation and to chemical products used during cultivation. For polyolephinic materials, mainly low density polyethylene, ethylene–butyl acrylate copolymers and ethylene–vinyl acetate copolymers, this results in a service life which ranges from some months up to 3–4 years relative to the thickness of the film and to the degree of stabilisation. Ethylene–tetrafluoroethylene copolymer films show much longer service life, because of the intrinsic UV stability of the polymer without the need of any UV stabilizer and because of the low chemical reactivity vs. the commonly used agrochemicals. A simple model was developed in order to compare ethylene–tetrafluoroethylene copolymer and polyolephinic films in terms of waste generation at the end of their service life. The quantity of waste generated during a period of 15 years by the replacement of the covering sheets for 1 ha of greenhouses was estimated according to the class of duration of the plastic films, in a climatic situation corresponding to Southern Italy. Field and laboratory tests were carried out on ethylene–tetrafluoroethylene copolymers and ethylene–vinyl acetate films in order to assess the film lifetime in real conditions, evaluating the effects of solar radiation and of the agrochemicals in terms of loss of tensile properties and of quantity of contaminants accumulated by the films. The results suggested that the use of ethylene–tetrafluoroethylene copolymer films as covering sheets of greenhouses can reduce the waste of plastic materials in a range from 5 to 10 times, with the further advantage of a significant recovery value for the used sheets.
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|Titolo:||Reduction of the Environmental Impact of Plastic Films for Greenhouse Covering by Using Fluoropolymeric Materials|
|Data di pubblicazione:||2008|
|Appare nelle tipologie:||1.1 Articolo in rivista|