Polyurethane [PU] is a class of polymers built up of carabamate linkages, which provide special characteristics to the material. It is the outcome of pioneering research work of Otto Bayer and his coworkers in 1937 at . Farben laboratories, in Leverkusen, Germany. Initial PU consisted of foams and fibres, while today, innovations and researches in the past decades have brought colossal changes in the world of PU.