Preparation of polyurethane coatings containing fly ash and determination of their mechanical, thermal and flammability properties

Polyurethane surface coatings, which are referred to as urethane coatings, are high-performance, high-elasticity, excellent abrasion-resistant and weather-resistant coatings that cure at low temperatures. Polyurethanes are widely used because of their different mechanical properties due to their segmented chemical structure and because they can be prepared in different forms from elastomeric films to sponges. Flexible foam walls used in footwear, furniture upholstery, and hard foam used in roof insulation, have a wide range of applications, from adhesives to automobile interior parts, from elastomers used in the flooring to leather sealants. Depending on the amounts and types of fillers present in the polymeric coatings, they also carry their properties to the polymer matrix. Fly ash is a combustion waste consisted of fine particles produced by thermal power plants used coal. Usage of fly ash as a filler in polymeric coatings as is very promising due to the excellent properties such as sphericity, porosity, light weight, low cost and high strength make it an affordable material for different applications. Because of these properties, fly ash particles can be used as special additives and fillers. Such evaluation of wastes can overcome the problem of storage and will make to avoid environmental problems, especially to save other limited natural raw materials, and to obtain better products in terms of quality and quantity. Different polyurethane combinations were prepared with using various isocyanate and diol combinations. To polyurethane coatings, fly ash was added by 2.5%, 5%, 10% and 15% by weight of the total mass by mechanical mixing method. The effects of fly ash amount on the polyurethane coatings upon mechanical properties, thermal and combustion behavior of polyurethane coating materials were investigated and compared with neat polyurethane coating. With addition of fly ash it was observed that the mechanical properties of the polyurethane coatings were get weakened while flammability properties were improved.