Polymer-based materials roofing membranes

Since little research had been reported on the application of thermal analysis (TA) methods to roofing, the committee recommended that more research be carried out to provide the technical basis for this application. The recommendation was based on research by Farlling and Backenstow and Flueler.I J These authors used TG, DSC, and DMA to characterize EPDM, PVC, and polymer-modified materials. Backenstow and Flueler reported the application of torsion pendulum analysis to characterize the above membrane materials. They concluded that TA techniques were useful for membrane characterization and should be investigated as methods for incorporation into standards. Previous work published by Cash on the use of DSC to characterize neoprene, chlorinated polyethylene (CPE) and PVC had shown that DSC could be used to identify not only the components in a single-ply sheet and the manufacturer, but also to differentiate between new and exposed materials. 

Polymer-modified bituminous membranes were developed in Europe in the mid- 1960s and have been in use in North America since 1975. The polymeric systems have varied from natural rubber to more complex synthetic systems sueh as block copolymers and polymer blends. Most common polymers used as modifiers are polyisobutylenes, polybutadienes, polyisopienes, styrene-butiene-monomer, styrene-butadiene-rubber, butyl rubber, ethylene-vinylaeetate (EVA), atactic polypropylene (APP) as well as natural rubber. Polymers, such as atactic polypropylene or styrene-butadiene-styiene (SBS), impart flexibility and elasticity, improve cohesive strength, resist flow at high temperatures, and toughness.1 1 They are the most widely used modifiers of bitumen-based roofing materials. 

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