PHOTOOXIDATIVE DEGRADATION OF POLYETHYLENE GREENHOUSE FILM IN A HARSHENVIRONMENT

Photo-oxidative reactions make a major contribution in reducing the li fetime of polymers. These reactions play a detrimental role in the dec ay of useful physical and chemical properties of polymers. In addition , high ultraviolet radiation, increased temperature and high humidity accelerate the degradation phenomenon in polymers. Natural weathering trials were conducted on samples of low density polyethylene greenhous e film in the harsh environment of Dhahran, Saudi Arabia. Greenhouse f ilm with a thickness of 180 mu based on low density polyethylene and s tabilized with hindered amine light stabilizer (HALS) and Ni-quencher was selected for this study. Samples were withdrawn monthly for a peri od of three years and the extent of the degradation was monitored by u sing Fourier Transform Infra-Red (FTIR) spectroscopy, Differential Sca nning Calorimeter (DSC), Mechanical Testing, Gel Permeation Chromatogr aphy (GPC) and Scanning Electron Microscopy (SEM).