Polyurethanes (PUs) are a special group of polymeric materials that are in many ways different from most of the other plastic types. They can be incorporated into many different items, such as paints, liquid coatings, elastomers, insulators, elastic fibers, foams, integral skins, etc. Several forms in which PUs appear today are mere improvements in the invention of the German professor (Professor Dr Otto Bayer) and his co-workers.1 Fig. 1 illustrates the most important types of PUs and some common examples of their uses. The invention of the diisocyanate polyaddition technique by these...