سنتز پلي هيدرازيد و پلي اكساديازول هاي سولفونه شده مرتبط; با توانايي تبادل پروتون جهت استفاده در پيل هاي سوختي

چكيده انگليسي :

Synthesis of Polyhydrazide and Related Sulfonated Polyoxadiazoles with Proton Exchange Ability for Membrane Fuel Cells Majid Maleki majid m364@yahoo com February 28 2012 Department of Chemistry Isfahan University of Technology Isfahan 84156 83111 I R Iran Degree M Sc Language FarsiDr A Abdolmaleki Email abdolmaleki@cc iut ac ir amirabdolmaleki@yahoo comAbstract In this project 5 hydroxyisophthalohydrazide as a monomer containing phenolic group was prepared in twosteps In first 5 hydroxyisophthalic acid convert to diethyl 5 hydroxyisophthalate as a diester intermediate Then this diester reacted wtih hydrazine to give monomer A series of novel hydroxyl containing polyhydrazides PHs were prepared by the solution polycondensation of new dihydrazide monomer with several aromatic diacidchlorides Optimized conditions in term of reaction time and temperature were studied and the influence of thetime of reaction on the inherent viscosity and the yield of the PH were examined According to these results oneequimolar of synthesized dihydrazide with one equimolar of different diacid chlorides were reacted first for 6 h at0oC and then for 12 h at room temperature and the resulting mixture was precipitated in methanol to obtainpolymers The resulting PHs exhibited good yields high thermal stability with inherent viscosities rangingbetween 0 30 and 0 65 dL g and were soluble in polar aprotic solvents The synthetic polymers were studied andcharacterized by FT IR 1H NMR elemental and thermogravimetric analysis TGA differential scanningcalorimetry DSC X ray diffraction XRD and field emission scanning electron microscopy FE SEM analysis This polyhydrazids have ability to convert to related sulfonated polyoxadiazoles Because of thepresence of phenolic groups in the main chain that can oxide in a specific electrochemical potential the polymersare electrochemical active Then the polymers were characterized and investigate with cyclic voltametric andelectrochemical impedance In the second part of the project a sulfonated polyoxadiazole were synthesized bythe polycondensation of 5 hydroxyisophthalic acid in poly phosphoric acid and presence of hydrazine sulfate Conditions in term of reaction time and other terms were optimized The ion exchange capacity IEC andsulfonation degree SD were high and show the polymer chains were sulfonated in reaction condition in goodyield Acids groups on polymer chains were neutralized which shows a high ability to absorb water as a hydrogel The polymer was characterized by FT IR elemental and thermogravimetric analysis TGA differential scanningcalorimetry DSC and field emission scanning electron microscopy FE SEM analysis In the next part a highmolecular weight sulfonated copolyoxadiazole was synthesized by the polycondensation of 5 hydroxyisophthalicacid and 4 4 diphenylether dicarboxylic acid in poly phosphoric acid and presence of hydrazine sulfate at hightemperatures The reaction conditions were optimized and the polymer was characterized by FT IR 1H NMR elemental and thermogravimetric analysis TGA differential scanning calorimetry DSC and field emissionscanning electron microscopy FE SEM The high thermal stable polymer was coverted to membrane by castingmethod The membrane shows good mechanical properties The ion exchange capacity IEC and sulfonationdegree SD were high and show the polymer chains were sulfonated in reaction condition in good yield Proton conductivity was 0 02 S cm 1 in good quantity This amount of conductivity is good and high in compareto Nafion and other same membranes This fast and high yield procedure that produces a heat resistance andhigh proton conductive membrane is not only of technologically but also of economically convenience comparedto multiple stage and same process Keyword Polyhydrazide Electrochemical active Sulfonated polymer Polyoxadiazole Hydrogel Proton exchangemembrane Fuel cell

ملكي، مجيد

سنتز پلي هيدرازيد و پلي اكساديازول هاي سولفونه شده مرتبط; با توانايي تبادل پروتون جهت استفاده در پيل هاي سوختي

OH فنولي , پليمر سولفونه , هيدروژل , ابر جاذب , غشاء تبادل پروتون