Preparation Of Cu-MOF/PLA For Melt Blowing And Study On Heavy Metal Adsorption

Polylactic acid?PLA?is used widely in many fields such as medical and health materials,adsorption filter materials,packaging materials,because of its good biocompatibility and degradation ability.However,the drawbacks of PLA,such as high melt viscosity,low elongation and brittleness,poor processability,easy degradation,which limits its application in meltblown nonwovens.Therefore,it is of great theoretical and practical value to improve the defects of PLA in the field of adsorptive filtration.In this paper,porous metal-organic frameworks?MOFs?are prepared by solvothermal method.The dimensional structure of the crystal material are formed by the self-assembly of multidentate organic ligands which contains nitrogen or oxygen with metal center.The sulfhydryl functionalized Cu-MOF was prepared by a facile coordination-based postsynthetic modification strategy,PLA was modified by melt blending with sulfhydryl functionalized Cu-MOF,and different ratio of Cu-MOF/PLA composites were prepared,the thermal stability,crystallinity and rheological properties of the composites were studied.The results were shown as follows:The specific surface area of Cu₃?BTC?₂ is 1381.1 m²/g,the pore volume is 0.52 m²/g,the pore size is 21.4 nm.Cu₃?BTC?₂ crystal was modified by 1,2-Ethanedithiol,The results of XRD showed that thecrystal form did not change and the crystallization intensity decreased slightly.FTIR results shows that the absorption peak at 673 cm^-1,2534 cm^-1,represent C-S and S-H stretching vibration peaks respectively,indicating that the sulfhydryl bond was successfully modified into the copper ion metal center of Cu₃?BTC?₂ crystal.By analyzing the absorption of Hg²⁺solution in a series of different concentrations,the optimum proportion of ethanedithiol was n(Cu²⁺):n?mercaptan?= 1:0.45.The intensity of the Cu-MOF/PLA composites diffraction peaks decreased slightly with theaddition of the modified Cu-MOF.DSC showed that with the addition of the modified Cu-MOF,the crystallization peak and melting peak area of Cu-MOF/PLA composites were increased compared with that of pure PLA.When the content of Cu-MOF was 2%,Xc of Cu-MOF/PLA composites reached to 30.42%.It was observed from the SEM that Cu-MOF had good compatibility with PLA matrix and dispersed uniformly in PLA matrix.With the increase of Cu-MOF content,Cu-MOF/PLA composites changed from brittle fracture to ductile fracture.The addition of modified Cu-MOF can improve the thermal stability and melt flow rate of Cu-MOF/PLA composites,so that it could meet the requirements of melt-blown nonwovens processing.The adsorption efficiency of Hg²⁺on the primary fiber was up to twice that of the modified Cu-MOF crystal.