Polyurethane Analysis

The first polyurethane synthesised by Dr Otto Bayer, in 1937, at IG Farbenindustrie Germany, by the reaction of a polyester diol with a diisocyanate, opened a new way in macromolecular chemistry: that is the synthesis of polymers by a new reaction, called polyaddition reaction. Polyurethane (PUR and PU) is any polymer composed of a chain of organic units joined by carbamate (urethane) links. Polyurethane polymers are formed through step-growth polymerization, by reacting a monomer (with at least two isocyanate functional groups) with another monomer (with at least two hydroxyl or alcohol groups) in the presence of a catalyst. Polyurethanes, having a relatively short history, of slightly more than 70 years, became one of the most dynamic groups
Polyurethanes have a large variety of applications due to their unique property range, such as high strength, high hardness, high modulus, and high elongation at break. Therefore, there are so many problems these materials can solve: from automotive parts to building and construction, from medicine to electronics, from textiles to furniture. Even so, this is not all (Prisacariu,
It is possible to synthesise the urethane groups by various methods, but the most important one is the reaction between an isocyanate and an alcohol: The first urethane was synthesised, by this route, as early as 1849 by Wurtz. In 1937, following very systematic and intensive research works at IG Farbenindustrie, in Germany, Dr. Otto Bayer synthesised the first polyurethane, by the reaction of a diisocyanate with a polyester having two terminal hydroxyl groups (called polyester diol, in fact an α,ω−telechelic polymer with terminal hydroxyl groups) (Mihail Ionescu, 2011): In fact, Bayer invented a new method for the synthesis of macromolecular compounds: the polyaddition reaction, which is a special case of polycondensation, with the difference that the reaction product is exclusively the polymer. In the classical polycondensation reactions, the products are: the polycondensation polymer and a low molecular weight (MW) compound (water, alcohols, and so on). The fact that in the polyaddition reactions the product is only the polymer is of great technological importance, especially for the purity and the morphology of the resulting macromolecular