Synthesis and properties of cyclic carbonates and non-isocyanate polyurethanes under atmospheric pressure

Abstract

Non-isocyanate polyurethane (NIPU) synthesized by cyclic carbonate resins (CC) and amines satisfies the growing awareness of environmental protection and attracts increasing research interest. However, CC are often prepared by CO2 and epoxy resin under high temperature and high pressure for a satisfactory conversion rate. This preparation process not only requires special equipment, but also causes the high cost of CC. To promote the synthesized method of CC, herein, we reported the successfully preparation of CC under atmosphere pressure with excellent properties. O-chloro alcohol resins were first synthesized by polyol reacted with anhydride and epichlorohydrin (ECH). This resins then reacted with sodium bicarbonate (NaHCO3) to offer CC under atmospheric pressure. The structures of CC were characterized by FTIR and 1H NMR. The NIPU were prepared with CC and amines at different molar ratios. It was found that the NIPU films exhibited high hardness up to 2H as well as good adhesion. It also has excellent thermal stability with the initial thermal decomposition temperature up to 260 °C (the molar ratio of CC: isophorone diamine (IPDA) = 1:1). To further improve the chemical resistance of NIPU film, the NIPU was modified with epoxy resins. We found that the NIPU film with 40 wt% of E-20 exhibited excellent chemical resistance. Surprisingly, this NIPU film also displayed excellent flexibility and good impact resistance (100 cm.kg).