Study On Preparation And Properties Of Polylactic Acid-based Degradable Composite Films

In this paper,polylactic acid(PLA)as the base material,acetyl tributyl citrate(ATBC),polyethylene glycol(PEG)and ethylene bis stearamide(EBS)as modifiers,by solution blend coating method to prepare PLA-based composite films.The structure and surface morphology of PLA-based composite films were characterized by FT-IR,XRD,SEM and AFM.It uses TG,DSC,DMA,tensile test and other means to examine the thermal stability and mechanical properties of PLA-based composite films.The degradation performance of PLA-based composite films was analyzed through high temperature and humidity soil burying degradation and UV radiation aging experiments.We try to modified PLA film using PEG4000,PEG6000 and ATBC respectively.Through tensile test,ATBC was found the most effective,which could make the elogation at break of PLA film reach 301.10%and 291.67%.TG and DSC tests were carried out on PLA/ATBC composite film.ATBC significantly reduced the glass transition temperature and melting temperature of PLA film and reduced their thermal stability.ATBC reduces the energy storage modulus of PLA film,while the loss modulus related peak widens,indicating that the addition of ATBC improves the flexibility of PLA molecular chain.The SEM image of PLA/ATBC composite film after the observation of 90d,cracks appeared on the surface of the composite film.And ATBC migrated and agglomerated in the PLA film,which.also reduced the service life of the film.With the right amount of PEG modified PLA/ATBC composite film,the tensile strength and elongation at break of PLA/ATBC/PEG composite film were improved,and the flexibility of the composite film was enhanced.PEG enhances the thermal stability of PLA/ATBC composite films,the melting temperature and decomposition temperature of the composite film were improved,and the 90d film SEM image was observed,and the surface cracks of PEG modified PLA/ATBC composite film was not produced and its service life was prolonged.The compatibility and processability of PLA-based composite films were improved by adding slip agent and dispersant,and the tensile properties and thermal stability of the composite films were further enhanced.PLA-based composite films were subjected to high temperature and humidity soil burying degradation and UV radiation aging experiments,and it was found that PLA-based composite films had good degradation performance.In the soil burying degradation experiment,the degradation rate of pure PLA film is relatively slow,and its final mass retention rate is the highest,while the degradation rate of PLA/ATBC composite film is the fastest.In the UV radiation aging experiment,the tensile strength of PLA-based composite films increased in a period of time after the UV radiation was started,and with the increase of ultraviolet radiation time,the tensile property of composite films decreased gradually.