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۱Novel Sulfonated Copolyimides as a Candidate for Proton Exchange Membrane Fuel Cell
نویسنده(ها): ،
اطلاعات انتشار: دومین همایش پیل سوختی ایران، سال
تعداد صفحات: ۴
Proton exchange membrane (PEM) fuel cells (polymer electrolyte membrane) are one of the most important types of fuel cells that employ a solid polymer electrolyte to separate the fuel from the oxidant. During last decades different polymers with various structures have been reported for application as membrane in stationary or mobile fuel cell systems. Sulfonated polyimides, polysulfones, polystyrenes, polybenzimidazoles, poly(ether ether ketone)s are some of the main types of membranes have been used recently [1,2]. Polyimides with appropriate ionconducting
sites are one of the best candidates for fuel cell membrane [3,4]. Here we intend to describe the preparation of some new sulfonated copolyimides as fuel cell membranes. Polyimide membranes with various degrees of sulfonation were prepared from a new sulfonated diamine (3,3'–Disulfonic acid–bis[4–(5–amino–1– naphthoxy)phenyl]sulfone or DANPS), two new unsulfonated diamines (4,4'–(5– amino–1–naphthoxy) diphenylsulfone or ANDS, and 4,4'–(4–Aminophenoxy) diphenylsulfone or APDS), and a six–membered ring dianhydride (NDA).<\div>

۲Physical and Mechanical Properties of Copolyimide based Fuel Cell Membranes
نویسنده(ها): ،
اطلاعات انتشار: ششمین کنگره بین المللی مهندسی شیمی، سال
تعداد صفحات: ۶
Physical and mechanical properties of four series of chemically and thermally stable sulfonated copolyimides as ion–conducting ionomers for application in fuel cell membrane, depending on chemical structure of diamine monomers were studied. The physical and mechanical properties of solid polymer membranes including thermal stability, mechanical strength, water uptake, water stability and morphology were evaluated. All the polymers were thermally stable. The SEM micrographs revealed that the hydrophobic–hydrophilic phase separation in polyimide was not occurred. Use of flexible monomers such as 4,4'–oxydianiline (ODA) and 4,4'–(4–aminophenoxy) diphenylsulfone (APDS) in the hydrophobic sequences increased the plastic behavior compared to rigid polymers prepared from 4,4'–(5– amino–1–naphthoxy) diphenylsulfone (ANDS) and m–phenylenediamine (m–PDA). It was concluded that the properties of polymeric films were strictly depended to chemical composition of monomers and molecular weight of copolymers.<\div>

۳Facile and low–cost method to fabricate a superhydrophobic aluminum alloy surface: towards optimum preparation conditions
نویسنده(ها): ، ،
اطلاعات انتشار: کنفرانس بین المللی علوم و مهندسی، سال
تعداد صفحات: ۵
Aluminum and the aluminum alloys are important and useful materials in industry with potential for enhanced applications via creating novel properties such assuperhydrophobicity and self–cleaning features. In this study, an improved facile and low–cost surface treatment approach was developed to create a superhydrophobicaluminum surface. Overall, the modified aluminum substrates exhibited a satisfactory superhydrophobicity, with a static water contact angle of about 1461 and a contact angle hysteresis of approximately 11. The effects of two key parameters including theetching time and coating temperature were investigated using simple and handy measurement techniques. The results show that a 4 min immersion time for acidtreatment of the surface and a temperature of 46 °C for the coating step would be considered optimal with respect to the contact angle and self–cleaning property. Further increasing the reaction temperature, however, leads to the cleavage of thehydrogen bonds, thus increasing the surface energy and reducing the water contact angle<\div>
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