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A sulfonated hyperbranched polyester (HPES-SO3H) was synthesized in order to prepare a proton exchange membrane. The modified hyperbranched polymer was characterized using 1H and 13C NMR and GPC. Hybrids of the modified polymer and polyether sulfone were prepared to incorporate sufficient entanglements and hence increase the mechanical properties of HPES-SO3H. The morphology of the films cast from the hybrids was studied using scanning electron microscopy (SEM), which confirmed the presence of a smooth surface with a controlled pore size. In order to enhance the proton conductivity and improve the mechanical properties of the obtained membrane, different loadings of sodium titanate nanowires (ST NWs), prepared hydrothermally, were added as fillers for the polymer hybrids. Membranes cast from pure polymer hybrids or nanocomposites were used to fabricate a membrane electrode assembly (MEA). It was found that a membrane composed of hyperbranched polyester with a 50% degree of sulfonation and immersed in H2SO4 for 2 h, had an open circuit potential of 0.9 V, compared with Nafion® which showed a potential of 0.85 V. Increasing the immersion time in H2SO4 solution to 12 h led to a sharp increase in current density to a value of 200 mA cm−2 and a power density value of 35 mW cm−2. Moreover, the results reveal that the addition of different amounts of ceramic material to the polymer hybrids has a negative influence on the membrane performance. Nevertheless, high proton conductivity was noticed in samples containing 1 wt% ST NWs. The good water swelling and mechanical properties of the obtained sulfonated polymeric hybrids, along with their cell performance being comparable to commercial membranes, make them promising candidates as proton exchange membranes for fuel cells.

Nanoblending hydrophilic nanofillers thoroughly into hydrophobic polymer matrices has long been challenging, especially if involving no pre-functionalization on a 1D ceramic nanomaterial. Here we report a facile approach to fine-tuning of sodium titanate (Na2Ti3O7) nanobelt’s (NB) surface chemistry widely by exchanging the NB’s crystal lattice cations, for successfully nanoblending the low-cost and versatile NBs into the poly(vinyl benzyl chloride) or p(VBC) and the sulfonated form of pVBC’s [or sp(VBC)] matrixes. For the first time, the adjustable nanocompositing showed a long-sought workability in not only in situ radical polymerization of VBC monomer but also ex situ nanoblending of the p(VBC), with the NBs. The resultant nanocomposites possess an unusual surface versatility that can be tailored from being hydrophilic to being hydrophobic by design. This method concludes a generalized and industry-viable approach to mass-producing nanocomposites of many types facilely at low-cost, especially for large scale industries such as packaging materials.

TiO2 nanowires (NWs) were prepared by hydrothermal treatment of TiO2 nanoparticles in alkaline medium, while hyperbranched polyester HPES-OH was prepared by polycondensation. Chemical structure of HPES-OH was confirmed by 1H and 13C NMR spectroscopy, FTIR and the molar mass was determined using gel permeation chromatography (GPC). Nanocomposites based on HPES-OH and TiO2 NWs are synthesized either by ex situ method or by in situ technique. Formation of the nanocomposites and investigation of their morphology were done using transmission electron microscope (TEM), scanning electron microscope (SEM) and X-ray diffraction (XRD). Photocatalytic activity of the synthesized nanocomposites compared to that of pure TiO2-NWs was studied. The chemical oxygen demand (COD) analysis confirmed the mineralization of wastewater via photocatalytic degradation. The results showed that not only photocatalytic activity of nanocomposites was much higher than that of the pure TiO2-NWs, but also the degradation time was reduced to large extent. This result can be attributed to reduction of the crystallite size produced due to the modification reaction. Durability of HPES-OH/TiO2 nanocomposites was investigated and the results confirmed that utilization of the modified TiO2-NWs in the second run was favorable, which suggests that strong adhesion between the NWs and HPES-OH was achieved through the formation of 2D structure.

Polypropylene/poly(methyl acrylate)-grafted glass wool (PMA-g-GW) mixes were prepared. The polymerization process was carried out using potassium persulfate (PPS) and PPS/acetone sodium bisulfite (ASBS) as a redox-pair initiation system at 60 and 70°C. The effect of using PPS or PPS/ASBS on the grafting percent and conversion percent reveals that the conversion percent values on using PPS as an initiator are higher than those of PPS/ASBS, while in the case of grafting, the inverse is true, that is, using PPS as an initiator gives grafting percent values lower than those that can be obtained using PPS/ASBS. The dielectric properties, thermal diffusivity, specific heat capacity, and thermal conductivity of PP loaded with modified glass wool as a function of different types and concentrations of initiators—used in the grafting polymerization process, namely, PPS and the redox initiating system—were also studied. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 723–732, 2003