Preparation Of Fully Biodegradable PLA/PBAT Material For Film And Research Of Film Blowing Process

In recent years,people's awareness of environmental protection had been enhancing,the current hot topic is research of fully biodegradable materials.In this paper,polylactic acid(PLA)and Polybutylene Adipate Terephthalate(PBAT)as matrix materials to prepared fully biodegradable films.Due to the film bubble of PLA/PBAT material is unstable in the process of blow molding,so the film obtained has low elongation at break and poor tear resistance.In this work,Long-chain Branched Compounds(LCB-PLAP)is obtained by Long-chain branched compounds(LCB-PLA),tetrabutyl titanate(TBT).Then LCB-PLAP will applied to PLA/PBAT system to improve the melting strength of PLA/PBAT.Ethylene-n-butyl acrylate-glycidyl methacrylate(EBA-GMA)and ethylene-acrylic acid copolymer grafted maleic anhydride(EAA-g-MAH)as compound compatibilizer was added to PLA/PBAT to improve the compatibility of PLA/PBAT materials.The influence of the process parameters of blown film on the tear resistance of the film was discussed in the same time Follows are the test results and conclusionsFor the viscosity-increasing modified PLA/PBAT material system,Long-chain branched LCB-PLAP has synthesized by LCB-PLA,PBAT and TBT..The results of FTIR,~1H NMR and GPC showed that TBT had a component of LCB-PLAP.Torque rheological experiments showed that the thermal degradation of LCB-PLAP had effectively inhibited.The rheological test showed that the addition of LCB-PLAP could improve the viscoelasticity of PLA/PBAT materials at low frequency region.When the addition mount of LCB-PLAP was 10wt%,the PLA chain and PBAT chain entanglement scale in PLA/PBAT materials was more lagrer.,and the Melt Flow Rate of PLA/PBAT materials was decreased from 6.7g/10min to 3.4g/10min.For the compatibilizing modified PLA/PBAT material system,when the mixture of EBA-GMA and EAA-MAH had synergistic effect,the mechanical properties tests and Molau experiments showed that when the addition mount of EBA-GMA and EAA-MAH was 4%,the break extension of the material was reduced from 186.9%to396.1%,,and the notched impact strength was increased from 6.3 KJ/m~2to12.5KJ/m~2,.TGA test showed that after added of compatibilizer E-(BA-AA)the thermal stability of PLA/PBAT had improved;DSC results showed that the addition of E-(BA-AA)hindered the crystallization of PLA/PBAT,and the crystallinity(X_c)decreased from 7.4%to 3.4%when the E-(BA-AA)addition was 4%.The PLA/PBAT material after viscosity-increasing and compatibilization modification has good blown film performance.The tear section of the prepared film has very obvious long and rough ligaments like whiskers;the longitudinal break extension was increased from 140.4%to 288.6%.The transverse break extension was increased from 110.4%to 220.4%,and the UV transmittance was increased from 60%to 70.6%.The orthogonal experiment showed that,the best process to obtain PLA/PBAT film which had good tear resistance that draft ratio was 20,temperature was 170?,freezing line height was 30mm.