Dynamic mechanical properties of single-ply roof coverings for low-slope roofs and the influence of water

Abstract

The results of five different commercial single-ply roof-covering products for low-slope roofs, i.e. atactic polypropylene (APP)-modified bitumen, styrene-butadiene-styrene copolymer (SBS)-modified bitumen, ethylene-copolymerized bitumen (ECB), plasticized PVC and ethylene-propylene-diene-methylene (EPDM)-rubber, studied by dynamic mechanical thermal analysis are summarized in this paper. Two samples of each product were tested, one which had only been conditioned at 20 °C, 50% relative humidity, and another which had been immersed in distilled water at 50 °C for 4000 h. The difference in the dynamic properties at the glass transition region of the two samples is discussed. The influence of water immersion on material properties such as T g and T onset was observed for the products of APP-modified bitumen, SBS-modified bitumen and plasticized PVC. The changes in these material properties may have significance for the durability of the products. Dynamic mechanical thermal analysis can be a useful tool for characterizing products used for single-ply roof coverings of low-slope roofs. It may be useful in understanding how different types of products behave in application with different types of dynamic stresses.