Study On The Modification Of Biodegradable Materials PBS And PBAT And Their Application In 3D Printing

Plastic waste has brought great harm to the environment.Biodegradable polymer materials can be naturally degraded without polluting the environment.They are an important means to solve environmental problems and have huge development space and application value.This paper studies the application of two biodegradable materials,polybutylene succinate（PBS）and polybutylene adipate/terephthalate（PBAT）,in FDM 3D printing.Firstly,the preparation process of PBS and PBAT printing filaments and the influence of printing process parameters on the mechanical properties of the printed specimens were studied respectively.The results show that if the melt flow rate（MFR）of PBS is too large,it is difficult to prepare FDM printing filaments,but its printing performance is good,and the tensile strength of the printed specimens is higher than that of the injection-molded specimens;PBAT is easy to be extruded and drawn to prepare filaments,but its filaments are soft and require special FDM equipment to print smoothly.The printing process parameters have a great influence on the performance of the printed specimens.Polylactic acid（PLA）was used for blending modification of PBS,and4,4’-diphenylmethane diisocyanate（MDI）and epoxy chain extender ADR were used as compatibilizers.The PBS/PLA blends was prepared by melt blending,and the effects of PLA addition and the type and amount of compatibilizer on the properties of PBS/PLA were studied.The results show that the modification effect of MDI is better than that of ADR.Adding 10wt.%PLA and 1wt.%MDI modifier can improve the mechanical properties and Vicat softening temperature of PBS,reduce MFR,and is beneficial to the printing wire.preparation.Under the FDM process parameters of printing temperature of260℃,printing speed of 20mm/s,filling density of 100%,and printing layer thickness of0.2mm,the comprehensive performance of PBS/PLA/MDI printed specimens is the best.PBAT was filled and modified with nano-CaCO₃,and the effect of nano-CaCO₃content on the properties of PBAT/nano-CaCO₃composite was studied.The results show that the addition of 10wt.%nano-CaCO₃can improve the mechanical properties of the material,increase the rigidity of the PBAT wire,and reduce the requirements for the printer.Under the FDM process parameters of printing temperature of 220℃,printing speed of20mm/s,filling density of 100%,and printing layer thickness of 0.2mm,the comprehensive mechanical properties of the PBAT/nano-CaCO₃composite printed specimens were the best.The PBAT/PBS blends was prepared by melt blending PBS and PBAT,and the effect of PBS and chain extender ADR addition on its properties was studied.The results show that the addition of 20wt.%PBS and 0.6wt.%chain extender ADR can significantly improve the mechanical properties of PBAT materials.Compared with pure PBAT,the tensile strength,elongation at break,bending modulus of the blends The volume and bending strength were increased by 20.74%,39.34%,39.38%and 27.27%,respectively.The best performance of the printed specimen is when the printing temperature is 270℃,the printing speed is 20mm/s,the filling density is 50%,and the printing layer thickness is0.2mm.The biodegradability of PBS,PBAT and their modified materials was studied by soil burial method and enzymatic degradation method,respectively.The results show that the degradation performance of pure PBS,pure PBAT and PBAT/nano-CaCO₃composites is better,the degradation rate measured by soil burial method at 180 days is higher than 25%.The degradability of PBS/PLA/MDI blends and PBAT/PBS/ADR blends is poor.