Degradation and stabilization of low-density polyethylene films used as greenhouse covering materials

A large quantity of plastics is used annually world-wide in the agricultural sector, of which a significant amount is intended for protected cultivation, in greenhouses and low tunnels. For this specific application, thin films of low-density polyethylene is the most widespread material used. As expected, due to the harsh conditions met during their use, from ultraviolet irradiation, heat, agrochemicals, as well as due to their limited thickness, such films degrade in a short time and often unexpectedly, creating both environmental problems and economic difficulties. In this paper, the most important mechanisms of degradation of low-density polyethylene agricultural films are described, giving emphasis on the special conditions and degradation parameters met during their use as greenhouse covering material. The methods of stabilizing such films, thus extending their service life, are also briefly discussed. (C) 2000 Silsoe Research Institute.