Polymers roofing membranes

We use the casting process to make polymer films (less than 0.3 mm thick) and sheets (more than 0.3 mm thick) for such diverse end uses as cling wrap, merchandise bags, roofing membranes, landfill liners, and the interior walls of refrigerators. During chill roll casting, molten polymer is extruded as a curtain from a slot die onto a chilled metal roller where it solidifies. The product is transported over a series of rollers to a winder where it is wound up. 

More than 800 million pounds of EPM and EPDM polymers were produced in the United States in 2001. Their volume ranks these materials fourth behind styrene-1,3-butadiene copolymers, poly( 1,4-butadiene), and butyl rubber as synthetic rubbers. EPM and EPDM polymers have good chemical resistance, especially toward ozone. They are very cost-effective products since physical properties are retained when blended with large amounts of fillers and oil. Applications include automobile radiator hose, weather stripping, and roofing membrane. 

A relatively new development which promises to gain in importance in the future is the modification of asphalt by butadiene-styrene block polymers.44 The block polymers help reduce the low temperature brittleness and impart resistance to flow at elevated temperatures. Applications in mastics, automobile body undercoatings and waterproofing materials such as high quality roofing membranes are envisaged. 

Davis, J.A. Hergenrother, W.L. McGillivary, D.R. Valaitis, J.K. Substituted Polybutadiene Polymer and Roofing Membrane Formed Therefrom. U.S. Patent 5,126,384, Jun 30, 1992 Bridgestone/Firestone. 

Major polymer applications wire and cable, autoignition wire, roofing membranes, technical hoses, power steering hose, transmission oil cooler hose, car axle boots, automotive air ducts and hoses, impact modification for PVC in pipe, vinyl siding, window profiles and FR ABS... 

Major polymer applications sealants, roofing membranes... 

More sophisticated calenders used to coat with the thermoplastic polymers give even more control. For example, with the proper choice of conditions, metal flakes can be oriented parallel to the surface which in roofing membrane increases their ability to reflect radiation. The precision of these machines offers very broad range of possible processing conditions. 

Polysar H DM. iiles/Pdysar Rubber] EPDM polymers for iig. mdding, hose and ptc e extrusion, sponge and cast coring, roofing membranes, black sidewalls. 

So far, in practice, there are various polymer-bitumen mixtures, such as PE-bitumen or elastomer-bitumen, including styrene-butadiene-styrene block copolymer (SBS)-bitumen or styrene-butadiene copolymer (SBR)-bitumen. The use of waterproof roofing membranes based on the thermoplastic elastomer-bitumen mixtures is increasing, especially in northern climate countries. 

With halogen-containing systems, zinc borate can partially or completely replace the antimony synergist in PVC, notably wire and cable, wallcoverings, roof membranes and tarpaulins. It is also effective in polyolefins, elastomers, polyamides and epoxy polymers while, in halogen-free systems, it can be used in conjunction with alumina trihydrate, magnesium hydroxide or red phosphorus. 

In a battery-dominant FCB, the LIB is recharged by an APU consisting of two small, 16-kW Hydrogenics polymer electrolyte membrane FCs (fueled by pressurized hydrogen in tanks on the bus roof). The Proterra battery-dominant FCB has operated for the past few years in Burbank, California, logging about 100 miles/day with the original RESS, proving its reliability and durability. 

The insulation system for pitched roofs usually provides the advantage of a continuous, homogeneous insulating layer with an economy in construction. Bitumen (asphalt) as well as its different versions modified with various polymers and a number of different roofing membranes, i.e., preformed or liquid applied sheets of PVC, terpolymer of ethylene-propylene-diene monomer (EPDM), chlorosulfonated polyethylene (Hypalon), PU, butyl rubber, polychloroprene (Neoprene) [36], all have been used as insulating layers. 

Ferro s Micro-Chek anti-microbial is an EPA-registered as an industrial antimildew agent for PVC, PIU and other polymers, particularly in stressful outdoor applications such as roof membranes. 

The main disadvantage is the high loading required for example about 60% Mg(OH)2 is needed to reach V-0 in polypropylene. Some synergists have been found to lower this level somewhat (10). The stiffening effect is less detrimental in softer polymers such as polyolefin or ethylene vinyl acetate cable jacket or TPO roofing membranes. 

As shown in Fig. 14.2, scrims made from polyester and/or glass fibres, and also scrim laminates made with glass or polyester nonwovens, are in use for many different polymer-based membranes. Scrims can often be found in roofing membranes made from PVC, PO, EPDM, or bitumen [9—12]. 

Most polymers used today are thermoplastics. Poiypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), and polystyrene (PS) often find application as low-end consumer items, packaging or others. Technical parts are produced mostly from acrylonitrile-butadiene-styrene-copolymer (ABS), polyamide (PA), polybutylene terephthalate (PBT), polyoxymethylene (POM), polyether sulfone (PES), polycarbonate (PC), polyphenylene sulfide (PPS), polytetrafluoroethylene (PTFE), polyether ether ketone (PEEK), or polyimide (PI). Polyvinyl chloride (PVC) is a material often used in building construction, especially for roofing membranes, window frames, and pipes, and its properties (rigid or flexible) are generally modified by additives. 

As can be seen in Fig. 2, there are essentially two families of polymer-based roofing membranes thermosets (TS) and thermoplastics (TP). 

A brief generic list of roofing membranes is given in Table 5. In each type, there is a long and growing list of products. No two products are identical even if they consist of the same predominant polymer. A manufacturer may have a number of different products unreinforced, or reinforced with different fabrics, for protected or exposed application, with different seaming techniques, different attachment methods, availability in different colors, etc. 

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