Structure And Properties Of Biodegradable PBS Composites Prepared By Vane Extruder

Unlike screw extruder which is based on the shear flow field, Vane Extruder which is dominated by elongational flow, inaugurates a new type of polymer processing device. Compared with the traditional screw extruder, the unique advantages of Vane Extruder are high mixing efficiency, well dispersive effect, low energy consumption, small in size, short thermal mechanical process, and the wide adaptability for materials processing. polybutylene succinate（PBS） has fully biodegradable, excellent processing and mechanical properties, but it still has the problem of poor thermal stability, slowing crystallization, low crystallinity and low melt strength, low relative molecular weight and low notched impact strength. Traditional screw plasticizing equipment to make better dispersion and mixing effect, increasing the shear rate is used to enhance its dispersive and mixing ability, but for biodegradable materials, strong shear stress area leads to strong degradation in processing, which influences its comprehensive properties.Therefore, in this paper biodegradable PBS composites were prepared by vane extruder based on dynamic elongational flow. Vane extruder has high mixing efficiency and well dispersive effect, and it also can reduce composites degradation during process because of its short thermal mechanical process, therefore vane extruder can realize the in-situ reinforcement of PBS blends during process.The nanoscale TiO₂（nano-TiO₂）-filled polybutylene succinate（PBS） composites and the ternary composites of PLA/PBS/CSW with different weight fractions were prepared by vane extruder, which is dominated by elongational flow. The morphologies, crystalline, thermal, dynamic viscoelastic, mechanical, and UV-resistance properties of these composites were analysed with SEM, XRD, DSC, TGA, DMA, mechanical test, and UV-resistance test. For the PBS/TiO₂ composites, results show that the crystalline structure of the PBS composites did not change with TiO₂ addition. Nevertheless, the introduction of TiO₂ has obviously improved the thermal stability, tensile modulus, flexural modulus, and flexural strength of the PBS composites. The UV resistance of the composites has also been significantly enhanced with TiO₂ addition. For the ternary PLA/PBS/CSW blends, results show that when the weight fraction of PBS is 50%, CSW has a preferential location in the PBS phase than in the PLA phase of the blend. DSC measurements and POM observation reveal that CSW has a heterogeneous nucleation effect on PLA and PBS matrix. The addition of PBS improves the crystallization of PLA and the thermal resistance of the PLA/PBS/CSW blends significantly. Furthermore, the tensile strength of PLA increases with the addition of CSW. With the increasing weight fraction of PBS, the tensile strength of PLA/PBS/CSW blends decreases in some extent, but the elongation at break of the blends increases significantly.Vane extruder which was a novel equipment based on generating global and dynamic elongational flow has the advantages of high mixing efficiency, well dispersive effect, reducing material degradation, and realizing the in-situ reinforcement of blends during process. These studies based on elongational flow theory provide an important theoretical and experimental basis to promote the development of biodegradable materials, advanced processing technology and equipment.