Preparation And Performance Study Of Ptfe-based Sintered Filter Material

Polytetrafluoroethylene(PTFE)has attracted wide attention among the public due to its unique advantages of excellent chemical stability and anti high and low temperature in recent years.Especially its high corrosion resistance and avirulence made it became an ideal raw for the preparation of sealant,filter medium and substitude materials for biologic gans.There was few study about PTFE filter materials in dosmestic at present,and the filter materials used in many fields were mainly imported from abroad with high price made them restricted on the applocation.So it was beneficial not only in theories but also in industrial production to explore the new preparation method of PTFE filter materials.PTFE-based sintered filter materials were prepared by a facile cold pressing and sintering method.The detailed fabrication method included according to the different formulations mixed PTFE with NaCl,PEG 1000,PEG2000,SiO2 in solvent,respectively.And then the mixture power was added into the mold and pressed into sheets with the thickness of 2mm.The prepared PTFE parions were taken out of the mold were sintered at 340,350,360,370,and 380 ℃ for 5h,and then remove the pore-foaming agent in distilled water to finished the preparation.The effects of performing duration,preforming pressure,additive amount of pore-foaming agent,sintering temperature on the average pore diameter,porosity,surface hydrophobicity,hardness,permeability were studied.The morphology changes of samples during sintering and pore micro-stucture were trackes though Scanning Electron Microscopy(SEM)analysis.The effects of sintering temperature and additive amount of pore-foaming agent on porosity was characterized by liquid immersion inspection.The surface hydrophobicity was researched though contact angle instrument.The hardness change of filter materials was characterized by durometer.The thermal stability were characterized by Thermogravimetric Analysis(TGA)and the chemical stability were measured by exploring the influence of powerful solvent immersion.Final,the effect of the kinds of pore-foaming agent on the sintered filter materials were explored by the comparison study of the permeating behavior though the four kinds of samples selected of gas and liquid.The final results of experiment show that the PTFE-based sintered filter material prepared by cold pressing and sintering method can possess the function of waterproof breathable.360 ℃ was the best sintering temperture.NaCl was the best pore-foaming agent and the optimal content was 20～30%.The gas flux maximum was 4000～7500 L/m2·h and the liquid flux maximum was 0.26～0.31 L/m2·h.And the porosity of the best sample prepared was 25～45%and its pore size was 1～1.38μm.It has a hydrophobic surface with WCA of 140～150°.And it 6has high thermal and chemical stability.