Abstract
Poly(lactic acid)/acetylated starch (PLA/AS) blends was prepared using a twin-screw extruder and two different types of single-screw extruder, respectively. One of the single-screw extruder was combined with conveying screw elements, providing shearing mixing, and the other with conveying screw elements and chaotic mixing screw elements, providing both shearing and chaotic mixing. To investigate the effect of processing methods on the rheological, thermal, and mechanical properties of PLA/AS blends, intrinsic viscosity tests, dynamic oscillatory rheological measurement, thermal analysis, tensile tests, and scanning electron microscopy were employed. Results show that the screw configuration of the extruder has a major influence on the properties of PLA/AS blends. Compared with PLA/AS blends prepared on the twin-screw extruder and on the single-screw extruder with shear mixing, improved dispersion of AS in the PLA matrix is found in blends produced on the single-screw extruder with chaotic mixing. The reason is that the interaction between PLA and AS phases is enhanced by chaotic mixing during the process of extrusion, facilitating to improving the thermal stability and tensile strength of the blend.
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