DURABILITY OF HALS-STABILIZED POLYETHYLENE FILM IN A GREENHOUSE ENVIRONMENT

Low-density polyethylene-based greenhouse films have been monitored fo r outdoor weather effects by mounting the film on a model greenhouse a nd on aluminum exposure racks at Dhahran plastic exposure facility. Th e change in chemical properties was monitored by Fourier transform inf rared (FTIR) spectroscopy. The thermal properties were observed by dif ferential scanning calorimetry (DSC) and the drop in percent elongatio n and stress at break was monitored. It is concluded that greenhouse f ilm mounted on the model greenhouse degraded more in comparison to the film on aluminum racks. The spectral emissions with wavelength betwee n 7 and 14 mu m are an important part of the energy losses from the so il and the plants inside a greenhouse. The partial prevention of the d issipation of this thermal energy from the greenhouse film during cool night hours creates a unique environment and influences the degradati on reactions in the plastic Nm. Pesticides, mostly sulfur- and halogen -based compounds, can also accelerate the degradation of the film.