Open Access

Humjeet Singh Gill Jagjit Singh

• The primary aim of this research project was to determine the effects of shearing on the structure of a blend of biopolymers (PLA+PBAT) through tailored screw designs in a twin-screw extruder. To achieve this, 3 different twin intermeshing co-rotating screw designs of an extruder were used. The designs were mainly focused on the kneading and mixing part of the screw which has a shearing effect on the biopolymer. The experiments were carried out by keeping the temperature, screw speed and feed rate constant. To carry out the experiment, a 60:40 blend of PBAT and PLA was utilized. The compounded pellets produced from the 3 screw designs were then used in a Blown Film machine. Furthermore, tensile test was conducted on the resulting samples. The shear strength and strain of the films were calculated. Tear test of the films were additionally carried out to validate the findings. Fourier Transform Infrared (FTIR) test was conducted to study the functional groups, identifying the chemical interactions and phase compatibility of the of PLA&PBAT blend. The results showed that the screw with 3 kneading blocks (HS) and 2 kneading blocks (MS) exhibited almost similar ultimate strength and ultimate strain. The screw design with only conveying elements had lower ultimate strength and strain. The kneading blocks played a role on the mixing and shearing of the biopolymer structure in the blend.