Thermal and rheological properties of fully biodegradable Poly(ethylene succinate)/Cellulose nanocrystals composites

The effect of low contents of cellulose nanocrystals (CNC) on the thermal and rheological properties of poly(ethylene succinate) (PES) was studied in this work in their fully biodegradable composites. Regardless of CNC content, the incorporation of CNC slightly improved the thermal stability and obviously enhanced the melt crystallization as an efficient heterogeneous nucleating agent as well as the complex viscosity, storage modulus, and loss modulus of PES as a rigid reinforcing nanofiller in the composites; however, the crystal structures of PES/CNC composites were not modified. The rheological behavior study indirectly revealed the content dependence of the dispersion of CNC in PES matrix, i.e., fine dispersion at low CNC contents of 0.5 wt% and below and aggregation at 1 wt% of CNC. Depending on CNC content, the external surfaces available for the nucleation of PES crystals were different due to the different dispersion states of CNC in polymer matrix. The morphology study confirmed that the melt crystallization of PES was apparently affected by the content and dispersion of CNC in the composites.