Remarkably enhanced crystallization behavior and impact toughness of poly(ethylene terephthalate) via introducing phenyl–terminated hyperbranched polyester

Rigid benzene ring structure on the backbone of poly(ethylene terephthalate) (PET) results in its slow crystallization rate. In present work, we proposed to incorporate a versatile nucleating agent with the combination of efficient heterogeneous nucleation and promoting crystal growth. Herein, phenyl–terminated hyperbranched polyester (HBP-Bz) was introduced. Polarized optical microscopy and differential scanning calorimetry results showed that HBP-Bz demonstrates superior heterogeneous nucleation effect. The crystallization temperature of PET is increased by nearly 20 K with the addition of 1% HBP-Bz. The main reason for HBP-Bz to accelerate PET crystallization is to increase the nucleation rate and density, and further increase in HBP-Bz content is favorable for the elevation of crystal growth rate of PET. A possible crystallization promotion mechanism of HBP-Bz on PET was proposed on the basis of dynamic viscoelasticity analysis. Moreover, effectively improved crystallinity and refined spherulites lead to remarkable elevation in mechanical properties especially the toughness.