Performance of multi-layered LDPE films used as greenhouse cover in semiarid climate.

The low-density polyethylene films used for greenhouse roof were naturally weathered for 9 months in harsh climatic conditions (Tiaret region, Algeria). The changes in the mechanical properties have been measured by tensile and creep-recovery tests. The measurements were carried out for both monolayer and tri-layer films. The anisotropic character of the films is preserved during ageing. The improvement in the creep resistance via cross-linking for both monolayer and tri-layer films affects different deformations. The results revealed that the degradation performance of these new tri-layer films is found to be quite better than that of the monolayer film, with regard to the mechanical properties.