The liquid-phase oligomer/polymerization of furfuryl alcohol (FA) catalyzed by homogeneous and heterogeneous acid catalysts was investigated by Infrared (IR) spectroscopy. At room temperature and 100 o C, FA was not decomposed with metal oxide catalysts except for tungsten oxide, whereas amberlyst and sulfuric acid converted a furfuryl alcohol monomer into oligomer/polymer even at a room temperature. During FA oligomer/polymerization reaction, a strong C=O band observed in the IR spectra provided a diketone structure, which was not observed in the Raman spectroscopy. Based on the FA monomer color changings and IR spectra, tungsten oxide can be possibly applied as a heterogeneous catalyst for controlling the product distribution and avoiding a product separation issue from catalyst.

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We have investigated thermal aging in the ionic conductivity of Nafion membranes being annealed at elevated temperatures using current sensing atomic force microscopy (CSAFM), a unique technique that allows simultaneous imaging surface morphology and surface conductance of the materials. The local current flows on the membranes show an increase after initial annealing, followed by a gradual decrease as the annealing continues. The current distribution extracted from CSAFM images shows that the decrease in the conductance follows approximately an exponential decay which occurs uniformly across the membrane. Least-square fits to the measured conductance versus time t yield time constants at the annealing temperature. Considering aging is a thermally activated process, we used an Arrhenius equation to describe the relationship between the time constant and the annealing temperature, which gives activation energies for the membranes. The activation energy yields following this process are 54 and 83 kJ/mol for Nafion 115 and Nafion NR212, respectively. These results provide guidance for employing the materials for device applications.