ABSTRACT
Polyurethanes are extremely large and complex molecules produced by combining a large number of simpler molecules called monomers. Monomers are compounds whose properties (molecular weight, boiling point, melting point, crystallinity, etc.) are discrete. Polyurethanes, on the other hand, typically do not have discrete properties but have average properties that represent a range of molecules with differing molecular weight and often slightly differing structure. Table 2.1 shows the comparison and contrast of the properties of typical small molecules with those of a polyurethane polymer.
