Synthesis and properties of non-isocyanate polyurethane coatings derived from cyclic carbonate-functionalized polysiloxanes

A series of novel cyclic carbonate-functionalized polysiloxanes (CC) were successfully prepared by the reaction of epoxy-functionalized polysiloxanes with carbon dioxide. Then the CCs with different carbonate content were reacted with various structural diamines such as isophorondiamine (IPDA), 4,4′-diaminodicyclohexylmethane (PACM), 1,2-proplenediamine (PDA) and 1,6-hexamethylenediamine (HMDA) to form non-isocyanate polyurethane (NIPU) coatings, respectively. The properties of the NIPU coatings were determined, and the effects of carbonate content as well as chemical structure of diamine on mechanical and thermal properties of NIPU coatings were investigated. The results showed that the cycloaliphatic amines cured coatings had higher tensile strength, Yong's modulus, water resistance and glass transition temperature compared to the aliphatic amines cured coatings. Furthermore, with the increase of the carbonate content, the tensile strength, Yong's modulus and glass transition temperature of the coatings were increased, while the thermal stability and water resistance of the coatings were decreased.