Polyurethanes – a review of 60 years of their syntheses and applications
The article is a review of development of polyurethanes (PUR) technologies during past 60 years. The problems, now being historical, concerning the preparation of raw materials: diisocyanates and diols (Scheme A) and classical macromolecular polyurethane compounds such as elastomers or foams (Fig. 1, 6) were discussed. PUR synthesis via gradual polyaddition (Fig. 2, 3), its kinetic modeling (Fig. 4, Table 1) and the process of reactive molding of polyurethane elastomers (Fig. 5) were presented. The newest technologies concerning the preparation of ecological PUR adhesives and varnishes based on ionomer type aqueous dispersions and the methods of production of core-shell type urethane-acrylic or urethane-siloxane copolymers are described. Selected examples of new applications of PUR are given: mechanically stable nanocomposites, biocompatible materials for medicine, liquid crystalline materials for electronics and optics. The problem of PUR waste management was mentioned (Fig. 7).
Key words: polyurethanes, diisocyanates, polyols, gradual polyaddition process, RIM method, kinetic modeling, ionomers, applications, polyurethane waste
Polyurethanes - a review of 60 years of their syntheses and applications