Effect of processing conditions on the rheological and mechanical properties of composites based on a PBS matrix and enzymatically treated date palm fibers

The rheological properties of biocomposites can change depending on the polymer, fiber type, fiber size and processing conditions. In this work, biodegradable PBS composites filled with raw and enzymatically treated date palm fibers were processed using an internal mixer. The influence of the processing conditions, namely filler concentration, rotor of the mixer rotational speed, as well as the type of the enzymatic fiber treatment on PBS (Poly Butylene Succinate)/date palm fiber composites were studied by measuring the torque and the temperature in real time during melt processing. A rheological analysis was also carried out by performing time and multi-wave-frequency sweeps. It was found that the stabilization torque increased with increasing fiber loading and rotor rotational speed, indicating a higher viscosity. An enhancement of the melting process occurred with modified fibers, which was explained by the decrease in the fiber diameter, denoting cellulose micro-fibrils separation by enzymes action. These composites were characterized by a better thermal resistance and mechanical stiffness compared to those based on raw fibers at the same loading rate.