ABSTRACT
In this study, changes on some physical properties of greenhouse covering materials produced by CO-EX techology with multi-layered CO-EX UV+IR+EVA and UV+IR+EVA+AD additives was investigated during their useful life of 24 months. As physical properties, global radiation and photosynthetically active radiation (PAR) transmittance of greenhouse covering materials were determined. Initial global radiation transmittances were determined as 92.7% and 83.6% for UV+IR+EVA and UV+IR+EVA+AD added PE, respectively. The plastic films of UV+IR+EVA and UV+IR+EVA+AD had losses of global radiation transmissions of 7.3% and 13.2% at the end of their useful life, respectively. These losses were due to accumulation of dust and dirt on the exterior surface of films. Initial PAR transmittance of UV+IR+EVA and UV+IR+EVA+AD films were determined as 80.1% and 83.0%, respectively. Both of the plastic films of UV+IR+EVA and UV+IR+EVA+AD had PAR transmission losses of 11.2 % and 14.0 % at the end of their useful life, respectively.
