Modification of a bitumen with various polymers for use in built-up roofing membranes

Bitumen, a mixture of aromatics, paraffins, asphaltenes and resins that rem ain after crude oil has been fractionally distilled, finds applications in blends with a proportion of a polymer, in built up membranes for the roofin g industry Blends of three commercially used polymers with a 100 penetratio n 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, differ ential scanning calorimetry (DSC) and dynamic mechanical thermal analysis ( DMTA). The blends prepared with these polymers displayed low temperature fl exibility and an onset of flow at high temperatures. The former characteris tic is required for use in cold environments the latter feature being a cri tical 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 fun ction in a manner that makes them suitable for the production of built-up r oofing membranes.