Rheological, mechanical, thermal, and morphological properties of blends poly(butylene adipate-co-terephthalate), thermoplastic starch, and cellulose nanoparticles

The objective of the present study was the preparation and characterization of poly(butylene adipate-co-terephthalate) (PBAT) and thermoplastic starch (TPS) blends reinforced with cellulose nanoparticles (CNCs) by extrusion. The work was conducted in four steps. Initially, the CNCs were prepared from eucalyptus cellulose pulp by acid hydrolysis. The second step was the preparation of the nanocomposite (TPS-CNC), composed of cassava starch, CNC, glycerol, and citric and stearic acids, by double screw extrusion. The third step was the preparation of PBAT/TPS-CNC blends in twin-screw extruders. In the fourth step, the films were produced by flat extrusion. Blends exhibited similar rheological behavior, increasing the CNC concentration in blends increased the viscosity as a function of the shear rate, and altered the behavior of the shear storage (G ') and shear loss (G '') curves as a function of the oscillation frequency (omega). The presence of CNC in blend provided improvements significant in mechanical properties, with 120% increase in Young's modulus, and 46% increase in maximum tensile. Thermal behavior (thermogravimetric analysis and differential scanning calorimetry) was altered with the incorporation of the CNC, showing a single melt peak (T-m) and a slight increase inT(g), indicating good dispersion between the phases of the blends, corroborating with the fracture surface microscopy of films.