پديد آورنده :
مومني، مهدي
عنوان :
ارزيابي نانوساختار در فرايند توليد غشاهاي الياف توخالي از محلول هاي پليمري شيشه اي با تكيه بر رفتار رئولوژيكي فاز غني از پليمر
مقطع تحصيلي :
كارشناسي ارشد
گرايش تحصيلي :
الياف پليمري
محل تحصيل :
اصفهان: دانشگاه صنعتي اصفهان، دانشكده نساجي
صفحه شمار :
هشت، 86ص.: مصور
استاد راهنما :
حسين فشندي، محمد ذره بيني
توصيفگر ها :
رفتار فازي سه تايي , خواص ويسكوالاستيك فازهاي غني از پليمر , بزرگ حفره
استاد داور :
صديقه برهاني، مرتضي صادقي
تاريخ ورود اطلاعات :
1394/12/10
چكيده انگليسي :
86AbstractPresently extensive use of polymeric membranes both in industrial applications andresearch is widely acknowledged In comparison to flat membranes hollow fiberpolymeric membranes due to their higher surface to volume ratio have attracted moreattention In certain applications morphological properties of the membranes are of vitalimportance Thus production of hollow fibers membranes with defined morphologypredominantly is conditional on prior identification of the parameters affecting themorphological properties of the hollow fiber membranes In this work the condition wasachieved by simultaneous investigation of phase behavior of three ternary systemscomposed of non solvent water solvent DMF glass polymers PS PEI PSf PES PMMA and rheological properties of the polymer rich phases Strictly speaking in thiswork for the first time superimposing rheological images on the ternary phase diagramwas considered as a powerful and promising tool to gain more insight into the poreformation within hollow fiber membranes The significant impact of the viscoelasticproperties of the polymer rich phases and the size of structure formation region SFR onthe morphology of hollow fibers was explained by comparing the morphology of themembranes prepared from the solution with the same phase behavior and also the samezero shear viscosity 0 The interplay of phase behavior and viscoelastic properties of thepolymer rich phases in determining the morphology of nano structured hollow fibermembranes was also investigated In this regard it must be noted that in systems withinstantaneous liquid liquid phase separation the mechanism of phase separation NG L nucleation and growth of polymer poor phase is dominant In such systems access tonanoscale pores less than 50 nm in membrane structure is solely attainable by controllingthe concentration of the initial solution as well as viscoelastic properties of the polymer rich phases This is achieved up on occurrence of phase separation through which thegrowth of the nascent nuclei is prevented due to the creation of polymer rich phases withhigh viscoelastic modulus G G In such systems the presence of polymer rich phasesin the upper layer slows down the penetration of non solvent into the sub layers This isfollowed by delayed phase separation based on SD spinodal decomposition mechanismin sub layers Hollow fiber membranes with an interconnected network of pores at thenanoscale and no macrovoids can be produced by selecting a three component system withdelayed phase separation based on SD mechanism and polymer rich phases with highviscoelastic modulus It was found that both the number and size of macrovoids in hollowfiber membrane structure not only is dependent on the 0 of spinning solution and liquid liquid phase separation time but also is a function of so far ignored viscoelastic propertiesof the polymer rich phases Keywords hollow fiber membrane nano structure ternary phase diagrams viscoelasticproperties of the polymer rich phases macrovoid
استاد راهنما :
حسين فشندي، محمد ذره بيني
استاد داور :
صديقه برهاني، مرتضي صادقي
