| Polylactic acid(PLA)can be made from the condensation of lactic acid which produced by fermentation of corn,corn stalks,sugar cane,cassava,kitchen waste,animal excrement,etc.It has good biological origin and can be completely biodegradable.The brittle and slow biodegradation speed of PLA which limit its application in the field of packaging materials,disposable plastic products and films;polyadipate-butylene terephthalate(PBAT)has the advantages of good toughness and fast biodegradation rate,but it has low strength and poor gloss.Composite system made from PLA and PBAT can complement each other.However,the solubility parameters of PLA and PBAT are quite different,resulting in poor compatibility.Therefore,this article adopt the method of compatibilizer compounding,respectively,ethylene-vinyl acetate grafted maleic anhydride(EVA-g-MAH)and ethylene-n-butyl acrylate(EBA)compound compatibilized PLA/PBAT composite system,ethylene-octene copolymer grafted maleic anhydride(POE-g-MAH)and ethylene-n-butyl acrylate(EBA)compound compatibilized PLA/PBAT composite system,The compatibility and mechanical properties of PLA/PBAT/starch blends were improved by POE-g-MAH and EBA.For the PLA/PBAT composite system with EVA-g-MAH and EBA compound capacity,the roughness of the cross section and the interior of the hole,tensile toughness,impact resistance and the compatibility of PLA phase and PBAT phase in the PLA/PBAT composite system could be increased by the addition of EVA-g-MAH and EBA.The viscosity,elasticity,and thermal stability of the melt was further improved by branched structure,molecular weight,and molecular weight distribution,and had no significant effect on the T_g,T_m,and crystallization properties of the composite system.For the PLA/PBAT composite system with POE-g-MAH and EBA compound capacity,the dispersion of PBAT in the PLA matrix was improved by addition of POE-g-MAH.The synergistic action of the two compatibilizers resulted in the formation of rough sections and holes in the material,which increased the energy required for the material during stretching and impact.After compatibilization,the impact toughness of the composite system could reach 32.4KJ/m~2,which increases431.1%,and the elongation at break was also increased from 22.4%to 81.8%.The compatibility of composite materials was significantly improved.From the analysis results of rheological test,differential scanning calorimetry(DSC)test,and thermal weight loss(TG)test,it could be known that with the addition of the compatibilizer,the branched structure formed in the composite system,and the crystallinity and thermal stability are significantly improved.For the PLA/PBAT/starch blend system with POE-g-MAH and EBA compound capacity,the compatibility of PLA/PBAT/starch blend system could be improved by compound capacity,and the dispersed state of starch in PLA/PBAT was improved.When the 25%starch and compatibilizer was added,the elongation at break and impact strength of the blend system could still reach 7.6%and 5.8 KJ/m~2.From the analysis results of rheological test,differential scanning calorimetry(DSC)test and thermal weight loss(TG)test,the viscosity,elasticity and thermal stability of PLA/PBAT/starch blend system could be increased by compatibilizer.Starch could be used as crystal nucleus to improve the crystallization properties of PLA. |
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