Study On The Microspheres Foaming Behavior Of PBAT/PLA Composite

Traditional foam products bring quite a lot of convenience to mankind.However,because the chemical properties of the matrix material of the traditional foam products are relatively stable and the volume is larger,it will bring a heavy burden to the environment after being abandoned and cause "white pollution".At the same time,the requirements of the equipment or technological conditions for the preparation of the traditional foam products are relatively high,which results in relatively large cost.Therefore,research and development of new biodegradable foam materials is of great significance.In this study,the environmentally friendly biodegradable materials PBAT and PLA were used as the matrix material,adding chain extender ADR4370 F and thermal expansion microsphere foaming agent to prepare PBAT/PLA blending composite and its composite microsphere foaming material by melt extrusion.The effects of dosage of microsphere foaming agent,PLA content and chain extender content on rheological behavior,crystallization behavior,mechanical behavior,microstructure and foaming behavior of the composites were investigated.The torque rheometer,X ray diffractometer(XRD),infrared spectroscopy(FTIR),differential scanning calorimeter(DSC),universal tensile test machine,gel permeation chromatography(GPC)and keen analyzer(TG)scanning electron microscope(SEM)were used to characterize the PBAT/PLA composite and its microsphere foaming material.The main contents and conclusions of this study are as follows:By using the single factor variable method,the effects of the content of microspheres foaming agent on the shear rheological behavior,apparent density,foam surface quality,springback rate,hardness and micromorphology of PBAT/PLA composite foam material were studied.The results showed that with the increasing of the content of microsphere foaming agent,the apparent density,surface quality and hardness of PBAT/PLA composite foam material gradually decrease,the springback rate and pore diameter increase first and then decrease,and the pore density increases gradually.When the foaming agent content is 4%,the composite foam materials have better comprehensive properties.Secondly,the effects of PLA content on shear rheological properties,melting index,mechanical properties,crystallization properties,compatibility,hydrophilicity and foaming behavior of PBAT/PLA blends were studied.The results showed that with the increasing of PLA content,the non Newtonian index,tensile strength and compatibility of the blends decreased first and then increased;PBAT and PLA are hydrophilic materials and when PLA content is 30%,contact angle is the largest;PBAT,PLA compatibility is poor,when PLA content is 30%,they are incompatible;And when the content of PLA is 10%,the crystallization property of PBAT/PLA blend composites is the best,the apparent quality of foam material is better,and the apparent density of foam material is the smallest.Finally,the effects of the content of chain extender ADR4370 F on the torque rheological properties,chain expansion behavior,mechanical properties,thermal properties,compatibility,hydrophile and microsphere foaming behavior of PBAT/PLA blends were studied.The results of infrared and GPC tests showed that the effect of chain expansion was remarkable,and with the increasing of chain extender ADR4370 F content,the balance torque of PBAT/PLA composite is increased gradually,the mechanical properties and thermal stability are improved,the compatibility is improved and the crystallization properties and hydrophilicity are decreased.When the content of ADR4370 F is 0.5%,the bubble size of the PBAT/PLA composite microspheres is relatively uniform,the density of the foaming material is the smallest and the surface quality is the best.