Fast curing of polyhydroxyurethanes via ring opening polyaddition of low viscosity cyclic carbonates and amines†
Aliphatic cyclic carbonate monomers (CCs) with two or three functional groups and low viscosity were synthesized by solvent-free catalytic transcarbonylation of oxiranes and carbon dioxide with high conversions at atmospheric pressure. Aminolysis of the CCs yielding polyhydroxyurethanes (PHUs) was studied by rheology. For this, different di- and triamines as well as low molecular weight branched polyethylenimine were used as amine compounds. The gelation time, pot life and final hardness of the PHUs were investigated. It was found that difunctional CCs and amines with low viscosity enable slow polyreaction, while trifunctional CCs can be used as high speed crosslinking agents. Based on these findings, different low viscosity mixtures of CCs and amines were explored for practical applications of tuneable PHUs.