Polyurethane from Sustainable Routes

Polyurethane (PU), the most versatile material among polymers, suffers the severe disadvantage of pollution. The normal precursors, isocyanates, are found to be toxic. At the end of its life, PU emits amines, which are also highly toxic. These substances have harmful effects on humans and the environment. Continuous contact with these chemicals leads to serious health problems such as dermatitis, conjunctivitis, asthma, and acute poisoning. Alternate reactants and reaction pathways are necessary. PUs can be synthesized from sustainable routes, and these routes are discussed in this chapter in detail. This chapter throws light on the possibilities of selecting derivatives, biobased materials, and sustainable routes in PU synthesis. The isocyanates can be easily replaced by alternatives, and the resultant materials are often called non-isocyanate PUs (NIPUs). The NIPUs can be obtained via rearrangement, ring-opening polymerization, polycondensation, and polyaddition reactions. NIPU is now commonly employed.