Preparation Of Nanoparticles Immobilized Porous Fibers Based On Polymer Blends And Their Catalytic Properties

Electrospun nanofibers are broadly used due to its high surface to volume ratio,can be prepared easily and get the desired fiber morphology.Recently,there have been more and more in-depth studies on electrostatic spinning porous fibers in many fields,such as biomedicine,filtration,separation,and catalysis.Therefore,in this work,PVDF and PLLA、POM and PLLA blends were used to prepare the PVDF/PLLA、POM/PLLA electrospun porous nanofibrous,the aminolyzed PVDF/PLLA and aminolyzed POM/PLLA porous nanofibrous,the palladium nanoparticles immobilized PVDF/PLLA and the palladium nanoparticles immobilized POM/PLLA nanofibrous.The catalytic properties of porous composite nanofibrous in catalytic reduction reactions were investigated.（1）Preparation of PVDF/PLLA porous nanofibrous by electrospinning.Porous PVDF/PLLA nanofibrous were fabricated by electrospining PVDF/PLLA blend solution.The effects of electrospinning conditions and solution parameters on fiber morphology were discussed,and the optimal spinning process was determined:PVDF/PLLA ratio was 50/50,solution concentration was 25%,spinning voltage was13kV.At last,PVDF/PLLA fibers with regular morphology and with a diameter of about 600nm were prepared.The porous PVDF/PLLA nanofibrous have been fabricated through chloroform etch.（2）Fabrication of PVDF/PLLA-Pd porous membranes and their catalytic performance.The aminolyzed PVDF/PLLA nanofibrous and porous structures were fabricated by aminolysis reaction.Aminolyzed PVDF/PLLA nanofibrous membranes were immersed into K₂PdCl₄ aqueous solution,allowing PdCl₄^2-ions to be complexed with the aminolyzed PVDF/PLLA amine groups,finally,we got PVDF/PLLA-Pd porous membranes by in-situ deposition method.The catalytic performance of PVDF/PLLA-Pd nanofibrous membranes were evaluated by catalytic reduction of 4-NA,when the content of Pd nanoparticles was 10.94%,the reaction constant was 21.7×10^-3s^-1.（3）Fabrication of POM/PLLA-Pd porous membranes and their catalytic performance in continuous flow catalysis.The POM/PLLA nanofibrous membranes were fabricated by electrospinning and aminolysis.Pd nanoparticles were immobilized on POM/PLLA fibers.The catalytic performance of the POM/PLLA-Pd nanofibrous membranes were well characterized and it was found that the first-order rate constant（k）of the reaction was 26.6×10^-3s^-1.The catalysis ability of POM/PLLA-Pd nanofibrous membranes in the different parameters,such as the coverage density of nanofibrous membranes,Pd loading,flow rate and the concentration of substrate in continuous flow catalytic were tested.Furthermore,POM/PLLA-Pd nanofibrous membranes have good reusability and storage stability,the conversion of 4-NA showed only slightly decreasing and the conversion efficiency still maintained above 99%after 4 using cycles.Moreover,the conversion efficiency keeps almost no change with even more than two weeks storage at room temperature.