Synthesis and characterization of new highly permeable polyamideimides from dianhydride monomers containing amide functions: An application to the purification of a fuel octane enhancer (ETBE) by pervaporation

Six polyamideimides (PAI) were synthesized from six dianhydride monomers containing amide functions. The dianhydride monomers were obtained from the reaction of trimellitic anhydride chloride with six aromatic diamines—1,4‐phenylenediamine, 2,2‐bis(4‐aminophenyl) propane, 4,4′‐oxydianiline, 4,4′‐methylenedianiline, 1,1‐bis(4‐aminophenyl)cyclohexane, and bis(4‐aminophenyl)sulfone—by a low‐temperature condensation with yields ranging from 35 to 98% depending on the monomer solubility in organic media. The monomers were characterized by Fourier transform infrared (FTIR) and ¹H NMR. In accordance with a synthesis scheme implying the reaction of a macrodiisocyanate with dianhydride monomers containing amide functions, six PAIs with a highly flexible soft block (polytetramethylene glycol PTMG 650) were synthesized with inherent viscosities ranging from 0.38 to 1.3 dL/g. Their characterization by FTIR and ¹H NMR fully confirmed their chemical structure. The strong physical crosslinking provided by polar hard blocks containing up to eight aromatic rings enabled the casting of PAI films that were very tough in the dry state and could withstand exposure to rather strong solvating media (e.g., ethers, alcohols, and chlorinated solvents). First experiments showed these materials could be good candidates for membrane‐separation applications. They revealed interesting features for the separation of organic aprotic–protic mixtures as shown by the first results obtained for the purification of a fuel octane enhancer (ethyl‐tert‐butyl ether) used in the European Community. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 614–630, 2000     

Partition Relations for Strongly Normal Ideals on Pκ(λ)

Building upon earlier work of Donna Carr, Don Pelletier, Chris Johnson, Shu‐Guo Zhang and others, we show that a normal ideal J on P_κ(λ) is strongly normal if and only if J⁺→< (J⁺, μ)² for every μ < κ, and we describe the least normal ideal J on P_κ(λ) such that J⁺ →< (J⁺, κ)².     

Gas transport properties of substituted PEEKs

Tert-butyl and di-tert-butyl were added as pendant groups to the ether-ether phenyl ring of poly(ether ether ketone), PEEK. tert-butyl PEEK, TBPEEK, was amorphous and di-tert-butyl PEEK, DBPEEK, was semicrystalline. However, a 2 : 1 random copolymer of TBPEEK and DBPEEK, TBDBPEEK, was amorphous. Gas transport of N₂, O₂, CH₄, and CO₂ through amorphous films of PEEK, TBPEEK, TBDBPEEK, and tetramethylbiphenyl PEEK were determined at 35°C and at pressures to about 15 atm. The results support previous observations that tert-butyl and tetramethylbiphenyl groups are very effective in disrupting chain packing in the polymer. For the present polymers, these substitutions led to a 5–18-fold increase in permeability, and, in some cases, at no loss in permselectivity. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35 : 2355–2362, 1997