Study On Preparation And Property Of Polylactic Acid Spunbonded Fabric

With the increasing awareness of environment protection and the shortage of oil resources,the development of environment-friendly biodegradable polymer materials has become thefocus. With good performance, polylactic acid has attracted much attention. The material ofcorn, wheat, rice and other starchy crops can be converted into lactic acid through thefermentation process. And then the polymer can be obtained by chemical synthesis. Richsource of raw materials brings a great potential in developing and studying the polylactic acidmaterial. Now, the polylactic acid has been made into fiber production successfully. Theproductions have great potential in the development of non-woven materials because of itsgood permeability and elasticity.In this paper, the study focused on how to get the PLA fiber and its spunbonded material.And the effect on the physical mechanical properties and the filtration performance of thenon-woven at different processing parameters was discussed.The airflow drafting is used in the spunbonding technology. The molten polymers areattenuated into fine filament fibers by the action of high airflow, and with the airflow thefibers are randomly gathered on the collector to form the webs. And then the webs areprocessed into the spunbonded materials by hot-pressing. The spunbonding technology has itsadvantages in the preparation of prepare the polylactic non-woven, because it only needs onestep to make the pellets become the nonwoven materials. And the simple processing makes itpossible to reduce the cost. Based on the content and characteristics of this paper, a largenumber of studies have been done on the following aspects in the research.Firstly, the basic properties of PLA pellets were studied, such as the glass transitiontemperature (Tg), melting point(Tm), crystallinity, thermal degradation, etc. And the flowproperties of molten polylactic were also studied by using the melt flow rate detector androtary rheometer. The results showed that the Tgand Tmis61.2oC and165oC, respectively,and the crystallinity is37.1%. PLA has a good thermal stability in a certain temperature range.Without any shear force, the melt has a better mobility with increasing temperature. PLA meltis a typical shear thinning non-Newtonian fluid. It provides a theoretical basis for settingprocess temperature in the preparation of PLA fiber and its spunbonded materials.And then, the PLA fiber could be got successfully with the experimental spunbondedmachines. The change of its properties at different drawing parameters was studied with theTensor and DSC. And the thermal properties and mechanical performance of PLA fiber werestudied during the physical aging process. The study showed that the crystallinity andbreaking strength would increase with the increasing of drawing, while the break elongationwould increase firstly and then decrease. During the physical aging process, there were twoglass transition zones on the heating curves of DSC, and the Tggradually moved to highertemperature, while the biggest force and breaking force of the fiber increased firstly andwould have a tendency to decrease.Finally, based on the successful preparation of fibers, the PLA spunbonded materials weremade successfully at different parameters. The mechanical performance was tested and the filtration property was studied with the Capillary Flow Porometer and Filter MaterialsComprehensive Performance Tester. The results showed its break elongation was very small,and there was no significant change in non-woven material strength with drawing increasing,while the pore size distribution gradually moved to the small pore direction and significantimprovement could be found in filtration efficiency. With the decreasing of the lapping speed,its physical mechanical properties became better, while the pore was decreases firstly and thenhad an increasing tendency. When the lapping speed was10m/min, the pore was smallest andhad a best filtration. With the increase of metering pump, its mechanical properties becamebetter, while the pore became big, and the filtration was bad.