Long-term Performances of New and Regenerated Polyethylene Membranes Used as Vapor Barriers in Temperate Climates

Long-term performances were assessed for nine polyethylene (PE) membranes used as vapor barriers and comprising virgin PE, 100% new PE, regenerated PE and multilayered virgin and regenerated PE. The membranes were evaluated and
compared using standard laboratory tests described by the standard EN 13859-1. Materials were assessed using five types of chemical analyses and seven physicomechanical tests. Chemical and mechanical properties were determined before and after exposure to an ageing regime comprising 168 days at 70 °C in total. Although the suppliers described the membranes only by the general term polyethylene, the chemical analysis suggested that all were based solely on low-density polyethylene, LDPE. Suppliers of the membranes stated that regenerated polyethylene was sorted, washed, cleaned, and enhanced with additives, including stabilizers. The study suggested that this treatment produced membranes with bulk properties similar to those of virgin and 100% new LDPE. However, visual examination of all membranes containing regenerated polyethylene showed additional particulate inclusions. This suggested that it is currently difficult to make membranes from regenerated polyethylene without physical defects. This study indicated that the content of regenerated PE in membranes, evaluated in this study, were not a significant factor in its performance. Importantly, measurement of their resistance to water vapour before and after being exposed to an ageing regime, indicated that all the membranes evaluated would perform satisfactorily as vapor barriers in buildings.