Three diamine monomers (ethylenediamine, butylenediamine, and p-phenylenediamine) were selected for cross-linking graphene oxide (GO) to prepare composite graphene oxide-framework (GOF) membranes through filtration using a pressure-assisted self-assembly technique. The membranes were applied to separate an ethanol−water mixture by pervaporation. Unmodified GO comprised only hydrogen bonds and π−π interactions, but after cross-linking it with a diamine, attenuated total reflectance−Fourier transform infrared and X-ray photoelectron spectroscopy demonstrated that the diamine was chemically bonded both to GO and the membrane support. Moreover, GO hydrophilicity was substantially altered; water contact angle increased from 24.4°to 80.6°(from cross-linking with an aliphatic structure of diamine to cross-linking with an aromatic structure). Results of X-ray diffraction showed that d-spacing in GOF layers varied from 10.4 to 8.7 Å. For GOFs presoaked in 90 wt % ethanol−water, covalent bonds between the layer and diamine could effectively suppress stretching of d-spacing. Cross-linking with ethylenediamine produced a composite membrane that exhibited a short interlayer dspacing and delivered an excellent pervaporation performance at 80 °C: permeation flux = 2297 g/(m 2 h); water concentration in permeate = 99.8 wt %. The membrane showed stability during a long-term operation at 30 °C for 120 h.

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Furan-containing benzoxazine monomers, 3-furfuryl-3,4-dihydro-2H-1,3benzoxazine (P-FBz) and bis(3-furfuryl-3,4-dihydro-2H-1,3-benzoxazinyl)isopropane (BPA-FBz), were prepared using furfurylamine as a raw material. The chemical structures of P-FBz and BPA-FBz were characterized with FTIR, 1 H NMR, elemental analysis, and mass spectrometry. Formation of furfurylamine Mannich bridge networks in the polymerizations of P-FBz and BPA-FBz increased the cross-linking densities and thermal stability of the resulting polybenzoxazines. P-FBz-and BPA-FBzbased polymers also exhibited high glass transition temperatures above 300 8C, high char yields, and low flammability with limited oxygen index values of 31. The dielectric (D k ¼ 3.21-3.39) and mechanical properties (high storage modulus of 3.0-3.9 GPa and low coefficient of thermal expansion of 37.7 -45.4 ppm) of the P-FBzand BPA-FBz-based polymers were superior or comparable to other polybenzoxazines.

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Crosslinked polymeric materials, which exhibit thermal remendability and removability through Diels–Alder (DA) and retro‐DA reactions, were obtained from using multifunctional maleimide and furan compounds as monomers. The synthesized monomers possess low melting points and good solubility in organo solvents to show excellent processing properties. The performance of DA and retro‐DA reactions were demonstrated with DSC and FTIR measurements. High performance of thermal remendablility and removability of the crosslinked materials were observed with SEM and solvent tests. These materials were applicable in advanced encapsulants and structural materials. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 905–913, 2006