Abstract
This work is a review of the main chemical properties of aliphatic and aromatic isocyanates and their advantages and disadvantages when used as precursors for polyurethane (PU) synthesis, to be applied as biomedical polyurethanes. Isocyanates react quantitatively with primary hydroxyl groups producing urethane groups. The presence of urethane groups can promote the restoration of living tissues. Molecules with two or more hydroxyl groups reacting with molecules containing two or more isocyanate groups results in PU, therefore PU is biocompatible, with the condition they have no remaining isocyanate groups and if all the precursor molecules from PU do not have damaging groups. Furthermore, this report describes the synthesis reactions of isocyanates used industrially and their advantages and disadvantages, alternative process as well as alternative compounds discussed in current articles, as isonitriles, carbamates, and new routes as transcarbamylase, blocked isocyanates, non-isocyanates, in order to suit the environmental and safety standards.
