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 agricultura l sector, of which a significant amount is intended for protected cultivati on, in greenhouses and low tunnels. For this specific application, thin fil ms of low-density polyethylene is the most widespread material used. As exp ected, due to the harsh conditions met during their use, from ultraviolet i rradiation, heat, agrochemicals, as well as due to their limited thickness, such films degrade in a short time and often unexpectedly, creating both e nvironmental problems and economic difficulties. In this paper, the most im portant mechanisms of degradation of low-density polyethylene agricultural films are described, giving emphasis on the special conditions and degradat ion parameters met during their use as greenhouse covering material. The me thods of stabilizing such films, thus extending their service life, are als o briefly discussed. (C) 2000 Silsoe Research Institute.