Modification of a Bitumen with Various Polymers for Use in Built-Up Roofing Membranes

Abstract

Bitumen, a mixture of aromatics, paraffins, asphaltenes and resins that remain after crude oil has been fractionally distilled, finds applications in blends with a proportion of a polymer, in built up membranes for the roofing industry. Blends of three commercially used polymers with a 100 penetration grade Nynas bitumen at levels between 9% and 29% w/w were prepared using a Z-blade mixer. The morphology, thermal and dynamic mechanical properties of these blends were examined using fluorescence optical microscopy, differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA). The blends prepared with these polymers displayed low temperature flexibility and an onset of flow at high temperatures. The former characteristic is required for use in cold environments the latter feature being a critical property when the membrane is manufactured and later when applied by the torching process on a roof. It may be seen how the different blends function in a manner that makes them suitable for the production of built-up roofing membranes.