Identification of the Polyethylene Grade Most Suitable for Natural Rubber-Polyethylene Blends used for Roofing Applications

In Sri Lanka, roofing materials are manufactured with clay, metal, plastic, wood and asbestos, and each of these has its own inherent drawbacks. Asbestos due to the economic advantages it offers, is now the most widely used roofing material in the country. However, it has scientifically proven health risks. The Government of Sri Lanka has initiated action to ban the use of asbestos as a roofing material. The focus of this study is on the development of a roofing material formed of rubber-thermoplastic blends containing Natural Rubber (NR) and Polyethylene (PE). Polyethylene is being currently used as a roofing material, but since it is lightweight it needs to be anchored tightly to the roof structure. Rubber being an energy absorbing material, can be incorporated into thermoplastics to make the latter more tough. Polymer blending is a current trend which is being used to develop technically advanced new materials from commonly available polymers. Polymer blends has an excellent combination of physicochemical properties of each of their parent materials. Sri Lanka exports natural rubber and thus there is a good opportunity to make value-additions to raw rubber exports. Similarly, the development of a new material will address the current problems associated with the use of asbestos as a roofing material. This study shows the most suitable grade of PE from among its most common grades such as High Density Polyethylene (HDPE), Low Density Polyethylene (LDPE) and Linear Low Density Polyethylene (LLDPE), for blending with natural rubber The best blended composition that will have standard properties of a roofing material such as tensile strength, tear strength, hardness, water absorption level, thermal conductivity etc.,. is then identified.