No abstract

A new oxetane‐containing polyether was synthesized by polycondensation of bisphenol‐AF (BPAF) with 3,3‐bis(chloromethyl)oxetane (BCMO) using the phase‐transfer catalyzed method. The polycondensation proceeded very smoothly in aromatic solvents, catalyzed by quaternary ammonium or phosphonium salts, such as tetrabutylammonium bromide (TBAB) and tetrabutylphosphonium bromide (TBPB), to afford the polymer with high yield and molecular weight. Further, a polymer with relatively high molecular weight was obtained when the reactions were carried out in aromatic and lipophilic solvents such as benzene and nitrobenzene. The modification of this oxetane‐containing polyether was easily achieved by carrying out ring‐opening of the oxetane ring by using hydrogen chloride in methylene chloride, which produced a functional polymer containing hydroxyl and chloro groups. The oxetane‐containing polyether was observed to be soluble in chlorinated aliphatic hydrocarbons such as methylene chloride and chloroform, as well as polar solvents such as DMSO, DMF, and DMAc, and also some common organic solvents such as benzene and toluene. However, it was insoluble in both aliphatic hydrocarbons as well as alcoholic solvents. The oxetane‐containing polyether was observed to start losing weight at around 300°C under nitrogen atmosphere, and 10% weight loss was measured to be 411°C. The glass transition temperature of the oxetane‐containing polyether was measured to be 134°C and the wide‐angle X‐ray diffraction pattern revealed this polymer to be semicrystalline. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 103–107, 1998

A new class of proton‐conducting polymer was developed via the sol–gel process from amino‐containing organic–inorganic hybrids by the treatment of poly(allylamine) with 3‐glycidoxypropyltrimethoxysilane doped with ortho‐phosphoric acid. The polymer matrix contains many hydrophilic sites and consists of a double‐crosslinked framework of polysiloxane and amine/epoxide. Differential scanning calorimetry results suggest that hydrogen bonding or electrostatic forces are present between H3PO4 and the amine nitrogen, resulting in an increase in the glass‐transition temperature of the poly(allylamine) chain with an increasing P/N ratio. The 31P magic‐angle spinning NMR spectra indicate that three types of phosphate species are involved in the proton conduction, and the motional freedom of H3PO4 is increased with increasing P/N ratios. The conductivity above 80 °C does not drop off but increases instead. Under a dry atmosphere, a high conductivity of 10−3 S/cm at temperatures up to 130 °C has been achieved. The maximum activation energy obtained at P/N = 0.5 suggests that a transition of proton‐conducting behavior exits between Grotthus‐ and vehicle‐type mechanisms. The dependence of conductivity on relative humidity (RH) above 50% is smaller for H3PO4‐doped membranes compared with H3PO4‐free ones. These hybrid polymers have characteristics of low water content (23 wt %) and high conductivity (10−2 S/cm at 95% RH), making them promising candidates as electrolytes for fuel cells. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3359–3367, 2005

No abstract

Novel ABA-type dumbbell-like water-soluble copolymers [D230(EI) 4 , D400(EI) 4 , and D400(EI) 8 ] were synthesized by introducing ethylenimine (EI) groups into both sides of polyoxypropylenediamines via a simple in situ ethylamination of polyoxypropylenediamine with 2-chloroethylamine hydrochloride. The structures of the resultant polymers were identified by Fourier transform infrared spectroscopy and 1 H NMR. The percentages of primary, secondary, and tertiary amine present were determined by the potentiometric titration method after treatments with the appropriate chemicals of salicylaldehyde and acetic anhydride. The surface tension and solubilizing behavior of pyrene in the presence of these polymers in aqueous medium were also investigated, and the efficiency to reduce the surface tension and solubilizing behavior of pyrene depends on the attachments of EI to polymer backbone. The chelating properties of these polymers were examined quantitatively by ultraviolet-visible (UVvis) spectroscopy in the presence of Cu 2ϩ ions in aqueous solution, and continuous variation analysis revealed that the most stable complex is formed at the normality ratio of [N]/[Cu 2ϩ ] ϭ 3.0. UV-vis spectroscopy and transmission electron microscopy were used to evaluate the dumbbell-like water-soluble copolymer, D400(EI) 8 , as a stabilizer for preparing colloidal noble metal nanoparticles (Au and Pt) in aqueous solution.