Polyethylene greenhouse cover aged under simulated sub-Saharan climatic conditions

The sand wind effect on the durability of low-density polyethylene (LDPE) used as greenhouse cover, kept under sub-Saharan climatic conditions, has been investigated. Sand winds were simulated with an apparatus developed in our laboratory. Infrared, UV visible spectroscopies, contact angle, interferential microscopy, differential scanning calorimetry and permeability measurements were performed on untreated samples and on samples submitted to a sand wind. The data analysis shows that the surface roughness is modified, leading to drastic decreasing of the UV-visible light transmission. This phenomenon is due to the presence of small sand particles inlaid in the sample surface and due to surface erosion. Sand wind does not affect O-2 permeation but decreases the rate of water absorption. Finally, in the range of experimental duration investigated in this work, no chemical action due to sand wind is observed. (C) 2002 Elsevier Science Ltd. All rights reserved.