Functional highly-stretchable semi-rigid poly(vinyl chloride) plastics via the addition of core-shell type star polyethylenimine-block-poly(ε-caprolactone)

Numerous plasticizers have been developed to acquire the traditional soft poly(vinyl chloride) (PVC) that is characteristic of a high elongation at break, but a low modulus of <70 MPa. Special highly-stretchable PVCs with high modulus (>70 MPa) are highly desirable for widening the application fields of PVC materials. Herein, a series of star copolymers with hyperbranched polyethylenimine (PEI) as core and poly(ε-caprolactone) (PCL) as shell (PEI-PCL) were utilized as plasticizers to prepare functional highly-stretchable semi-rigid plasticized PVC materials. Under the 0.5 weight ratio of PEI-PCL to PVC, the obtained plasticized PVCs showed the highest modulus of around 392 MPa under the assuring of >400% elongation at break, which was nearly four-fold of the most rigid plasticized PVC materials ever-reported. Through the further DSC and FTIR characterizations and the comparison with linear PCL plasticizers, the reason for so rigidity was ascribed as that the guest-encapsulation capability of PEI-PCLs led to the physical crosslinking of PVC chains by the amidated PEI core through the dense hydrogen-bonds. Furthermore, PEI-PCLs could disperse hydrophilic dyes homogeneously into PVC matrix, resulting in colorful or photoluminescent PVC materials.