Effect of castor oil/polycaprolactone hybrid polyols on the properties of biopolyurethane

Organic solvent soluble castor oil/polycaprolactone diol (PCL) based polyurethane for artificial leather was prepared by a one-step polymerization with 4,4′-diphenylmethane diisocyanate (MDI) at different castor oil contents. The PCL and MDI acted as soft and hard segments, respectively, and the castor oil acted as a dendritic point in the castor oil/PCL based polyurethane structure. The tensile properties and shape memory of castor oil/PCL based polyurethane were enhanced remarkably, compared with the PCL based polyurethane because of the increased hard segment portion and crosslinking density by the three urethane bonds formed per molecule in the castor oil/PCL mixed system. The dynamic mechanical analysis showed that the storage modulus of castor oil/PCL based polyurethanes increased with increasing castor oil content. In the enzymatic degradation test, castor oil/PCL based polyurethane degraded faster than conventional petroleum based polyurethane. This research suggests the potential to use the castor oil/PCL based polyurethane as a biobased coating materials.