Diffuse reflectance infrared (IR) spectroscopy performed over a wide temperature range (35-298 K) is used to study the dynamics of H(2) adsorbed within the isostructural metal-organic frameworks M(2)L (M = Mg, Mn, Co, Ni and Zn; L = 2,5-dioxidobenzene-1,4-dicarboxylate) referred to as MOF-74 and CPO-27. Spectra collected at H(2) concentrations ranging from 0.1 to 3.0 H(2) per metal cation reveal that strongly red-shifted vibrational modes arise from isolated H(2) bound to the available metal coordination site. The red shift of the bands associated with this site correlate with reported isosteric enthalpies of adsorption (at small surface coverage), which in turn depend on the identity of M. In contrast, the bands assigned to H(2) adsorbed at positions >3 Å from the metal site exhibit only minor differences among the five materials. Our results are consistent with previous models based on neutron diffraction data and independent IR studies, but they do not support a recently proposed adsorption mechanism that invokes strong H(2)···H(2) interactions (Nijem et al. J. Am. Chem. Soc.2010, 132, 14834-14848). Room temperature IR spectra comparable to those on which the recently proposed adsorption mechanism was based were only reproduced after contaminating the adsorbent with ambient air. Our interpretation that the uncontaminated spectral features result from stepwise adsorption at discrete framework sites is reinforced by systematic red shifts of adsorbed H(2) isotopologues and consistencies among overtone bands that are well-described by the Buckingham model of molecular interactions in vibrational spectroscopy.

This paper reviews some modern aspects and trends in the development of high performance polymer materials and processing technologies providing fabrication of advanced film and film structures. Changes in understanding of technical requirements and properties, along with novel approaches in creating high performance films of various thermoplastic materials, are discussed. The most important groups of polymer materials being used in high performance applications are described.

Low-temperature diffuse reflectance infrared spectroscopy is used to measure the quantum dynamics of molecular hydrogen and its isotopologues adsorbed in the microporous material MOF-74. At least two distinct adsorption sites are revealed by increasing the concentration of H 2 within the material and monitoring the successive appearance of absorption bands with decreasing bathochromic shifts ͑or "redshifts"͒ from the unperturbed ͑gas-phase͒ vibrational frequencies. Under conditions wherein both the primary and neighboring secondary sites are occupied, additional frequency shifts are observed that confirm the interactions among the adsorbed molecules are non-negligible. Ortho to para conversion of the adsorbed normal-H 2 is observed to occur within minutes and this process is accelerated when both primary and secondary sites are occupied. Translational sidebands are also observed, providing an estimation of 124 cm −1 for the frequency of the center-of-mass motion of H 2 at the primary adsorption site. The frequency shifts of the absorption bands of HD and D 2 diverge from the predictions of a simple isotope effect, emphasizing the importance of the zero-point energy contribution.

We have studied the phenomenon of acoustic cavitation under the action of volume ultrasonic oscillations on polymer melts and filled compositions. This phenomenon and the stress state of the material have been studied by means of a device for the visualization of flow in polarized light. It has been shown that the process of' cavity formation in high-viscosity systems has a certain threshold and that the critical amplitude of oscillations depends on the duration of ultrasonics action. The effect of acoustic field on the melts of commerical polymers and filled compositions results in structural changes. In addition, a sharp increase of the melt flow is observed. Model experiments have shown that the size of particles and filler distribution can also be changed by utrasonic oscillation.

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