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This paper reports the synthesis and characterization of a series of new semi-fluorinated sulfonated copolyimides (co-SPI) using a new trifluoromethyl and phosphine oxide containing diamine monomer, namely bis[4-(4 ′ -aminophenoxy)-3-trifluoromethyl phenyl] phenylphosphine oxide (DFPPO). The copolymers were prepared by one pot polycondensation reaction of a mixture of two diamine monomers, namely 4,4 ′ -diaminostilbene-2,2 ′ -disulfonic acid (DSDSA) and DFPPO with the equimolar amount of 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA). All these copolymers were soluble in several organic solvents and size exclusion chromatography indicated the formation of high molar masses. The membranes prepared from these copolymers by solution casting route showed good mechanical properties. The polymers were characterized by FTIR and NMR spectroscopic techniques that confirmed the polymer repeat unit structures. The degree of sulfonation of the copolymers was determined from 1 H NMR signal intensities. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) images of the membranes showed phase separated morphology. In general, all the copolyimides showed high proton conductivity and reasonably high oxidative and hydrolytic stability. The co-SPI membrane DFPNH-90 (90% degree of sulfonation) with IEC W = 2.86 mequiv g −1 showed proton conductivity as high as 237 mS cm −1 at 80 °C. [ABSTRACT FROM AUTHOR]

Two novel fluorinated diimide-diacid monomers, [2,2′-(4,4′-(4′-chloro-3′-(trifluoromethyl)biphenyl-2,5-diyl)bis(oxy)bis(3-(trifluoromethyl)-4,1-phenylene))bis(1,3-dioxoisoindoline-5-carboxylic acid)] (III) and [2,2′-(4,4′-(3′,5′-bis(trifluoromethyl)biphenyl-2,5-diyl)bis(oxy)bis(3-(trifluoromethyl)-4,1-phe-nylene))bis(1,3-dioxoisoindoline-5-carboxylic acid)] (IV), were respectively designed and synthesized viathe reactions between the diamine (I or II) and two molar equivalents of trimellitic anhydride. Based on these two diimide-diacids, two families of novel poly(amide-imide)s (PAIs) (IIIa–IIIe and IVa–IVe) bearing different trifluoromethyl groups were prepared by directly polymerizing diimide-diacids with a series of aromatic diamines (a–e). All of the PAIs exhibited high glass transition temperatures ( T g s, 236–268 °C), excellent thermal stability (only 5% weight loss at 493–542 °C under nitrogen) and good solubility in various organic solvents since the bulky pendant groups were introduced. The cast films of these PAIs (thickness = 80–90 μm) had excellent optical transparency (70–83% at 450 nm, 85–87% at 550 nm and 88–89% at 800 nm) and low dielectric constants (2.62–2.92 at 1 MHz). In addition, the spin-coated films of these PAIs presented very low birefringence values the minimum of which was 0.0073 at 650 nm. These spin-coated films also exhibited very weak absorption at the near-infrared communication wavelengths of 1310 and 1550 nm. [ABSTRACT FROM AUTHOR]

A series of fluorenyl and trifluoromethyl groups containing co-poly(ether imide)s (S-co-PIs) have been prepared from a new diamine monomer; 9,9-bis(3-methoxy-4-(4-amino(3-trifluoro-methyl)biphenoxy)phenyl)-9H-fluorene (APHPF). The polymers were prepared by the polycondensation reaction of 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA) with two different diamines; APHPF and 4,4′-diaminostilbene-2,2′-disulfonicacid (DSDSA) as a co-monomer. The monomer and polymers were well characterized by 1 H NMR and ATR-FTIR spectroscopies. The co-polymers were soluble in various organic solvents and membranes were prepared from solution cast route. The S-co-PIs showed high thermal and mechanical stability. TEM and AFM results supports the formation of phase separated morphology with well separated ionic-clusters. All these S-co-PIs displayed reasonably high proton conductivity. One of the copolymers (DAN-80; IECw ∼2.27 meq g −1 ) exhibited a proton conductivity as high as 149 mS cm −1 which was comparable to that of Nafion® 117 (165 mS cm −1 ) at 80 °C. The co-polymers maintain a good balance between water-uptake and swelling ratios and peroxide resistance. Microbial Fuel Cell (MFC) performance of the co-polymers were evaluated DAN-80 exhibited a similar performance like Nafion® 117 under similar test condition. [ABSTRACT FROM AUTHOR]

Abstract: Random copolyimides were synthesized using diamino functional room temperature ionic liquid (RTIL) and were characterized. Specifically, a diamino functional RTIL, 1,12-di[3-(3-aminopropyl) imidazolium] dodecane bis[(trifluoromethyl)sulfonyl] imide ([C12(DAPIM)2][Tf2N]2), was reacted with 2,2-bis(3,4-carboxylyphenyl) hexafluoropropane dianhydride (6FDA) and m-phenylenediamine (MDA) to form random cooplyimides with a [C12(DAPIM)2][NTf2]2 concentration varying from 10 to 30mol%. Incorporation of [C12(DAPIM)2][NTf2]2 within the 6FDA–MDA backbone resulted in decreases in the polymer thermal stability, glass transition temperature, d-spacing, fractional free volume and increments in density. The gas permeability, solubility and diffusivity of the random copolyimides decreased and the permeability selectivities increased compared with the pure 6FDA–MDA polyimide. [Copyright &y& Elsevier]