Manual applied polyurethane-urea: High performance coating based on CO2-based polyol and polyaspartic ester

Brushable polyurea based on slow reactive process was prepared by simple, mild and solvent-free method. Firstly, polyurethane prepolymer was synthesized from poly (propylene carbonate) diol (PPCD, copolymer of propylene oxide/CO2) and 4,4 '-dicylocyhexylmethane diisocyanate (HMDI). Polyurethane-urea (PPCD-PUU) was then obtained by the chain extension of prepolymer with polyaspartic ester (PAE). The mechanical prop-erties of PPCD-PUU were optimized by adjusting the content of -NCO in the prepolymer and the ratio of pre -polymer to PAE. The mechanical strength, thermal resistance, solvent resistance and hydrolysis resistance of PPCD-PUU were compared with those of PUUs derived from polypropylene glycol and poly-caprolactone diol. The results showed that the comprehensive mechanical properties of PPCD-PUU were balanced when the R value was 1.15 and the content of -NCO was 8 %. The tensile strength was 20.5 MPa, the elongation at break was 352 %, and the Young's modulus was 168.2 MPa. Especially, after soaking in 10 % H2SO4 aqueous solution, 10 % NaOH aqueous solution and 10 % NaCl aqueous solution for 24 h, the tensile properties were basically un-changed. Manual applied polyurethane-urea based on commercial PPCD has broad application prospects because it avoids the use of expensive spraying equipment.