Study on synthesis of polycarbonate dilate polyurethane elastomers

Polyurethane (PU) elastomer was synthesized from the polycarbonate diol (PCDL) and isoflurone diisocyanate (IPDI) in N, N-dimethylformamide (DMF) solvent by the prepolymer method. The structure and molecular weight of PCDL manufactured in laboratory were characterized and the effect of the ratio of isocyanate group to hydroxyl group (R value) on the structure and properties of PU elastomer was investigated. The structural characterization of PCDL demonstrated that the structure of PCDL was consistent with the theoretical structure, and that the molecular weight was 3330. FI-IR proved that PU elastomer was successfully prepared in this experiment. When R value is equal to 1.0, the elongation at break reaches the maximum of 646.2%, and decreases with the increase of R value. Also, the transmittance reaches the highest of 90.0%, and it decreases with the increase of R value. When R value is equal to 1.3, the maximum tensile strength of PU elastomer reaches 23.90 MPa, and the maximum Td5% reaches 296.0 °C. When R value is equal to 1.4, the lowest Td5% is 289.0 °C, and the transmittance is also the lowest, reaching 70%. The glass transition temperature of hard chain (Tgh) is up to 64.2 °C and decreases with the decrease of R value. However, glass transition temperature of soft chain (Tgs) shows little change with the increase of R value, which is about − 30 °C.