TY - CONF A1 - Böhning, Martin A1 - Goering, Harald A1 - Hao, Ning A1 - Schönhals, Andreas T1 - Gas Transport in Polymer based Nanocomposite Systems T2 - Workshop "Glasübergang" CY - Rostock, Germany DA - 2002-12-16 PY - 2002 AN - OPUS4-2054 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hao, Ning A1 - Böhning, Martin A1 - Schönhals, Andreas T1 - Dielectric Properties of Nanocomposites Based on Polystyrene and Polyhedral Oligomeric Phenethyl-Silsesquioxanes N2 - Nanocomposites were prepared by solution blending of polyhedral oligomeric silsesquioxane with phenethyl substituents (PhenethylPOSS) into polystyrene (PS). The prepared materials were investigated by dielectric spectroscopy, differential scanning calorimetry (DSC), and density measurements. Additional FTIR investigations were carried out. Pure polystyrene shows two relaxation processes, an intermediate β*-process at lower and the α-relaxation at higher temperatures, the latter corresponding to segmental dynamics (dynamic glass transition). The molecular assignment of the β*-process needs further investigation. PhenethylPOSS can be incorporated into PS up to about 40 wt % without any indication of phase separation. With increasing PhenethylPOSS content, the α-relaxation of the composites shifts to lower temperatures and the loss peak broadens. Thus, the main effect of the nanofiller in the polystyrene matrix is to enhance the segmental dynamics, i.e., plasticization. The incorporation of approximately 40 wt % (approximately 5 mol %) PhenethylPOSS shifts the glass transition temperature Tg by 50 K to lower temperatures. The obtained results for polystyrene are discussed together with those reported recently for polycarbonate where a phase-separated morphology is observed for higher concentrations of PhenethylPOSS. The different behavior of PhenethylPOSS in polystyrene and polycarbonate is interpreted in terms of the different interaction of the phenyl rings within the POSS substituents with the phenyl rings of the polymers. For polystyrene, the interaction is stronger than for polycarbonate which probably leads to the enhanced miscibility of PhenethylPOSS into polystyrene. A detailed analysis of the temperature dependence of the dielectric relaxation strengths points also to additional interactions in the nanocomposites when compared to pure polystyrene. The broadening of the loss peak with increasing concentration is discussed in the framework of composition fluctuations. KW - Polyhedral oligomeric silsesquioxane (POSS) KW - Polymer-based nanocomposites KW - Broadband dielectric spectroscopy KW - Polystyrene PY - 2007 DO - https://doi.org/10.1021/ma071777g SN - 0024-9297 SN - 1520-5835 VL - 40 IS - 26 SP - 9672 EP - 9679 PB - American Chemical Society CY - Washington, DC AN - OPUS4-16492 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schönhals, Andreas T1 - Gas transport properties of polymeric nanocomposites based on polyhedral oligomeric silsesquioxanes T2 - Meeting America Chemical Society CY - Boston, MA, USA DA - 2007-07-19 PY - 2007 AN - OPUS4-15354 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schönhals, Andreas T1 - Structure property relationship of polymeric nanocomposites based on polyhedral oligomeric silsesquioxanes T2 - Jahrestagung der Deutschen Physikalischen Gesellschaft, AK Chemische Physik/Polymerphysik CY - Regensburg, Germany DA - 2007-03-26 PY - 2007 AN - OPUS4-14591 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schönhals, Andreas T1 - Structure property relationships of different polymer based nanocomposites as investigated by dielectric spectroscopy and gas transport measurements T2 - European Polymer Congress 2007 CY - Portorož, Slovenia DA - 2007-07-02 PY - 2007 AN - OPUS4-14952 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hao, Ning A1 - Böhning, Martin A1 - Schönhals, Andreas T1 - Structure Property Relationships of Polymeric Nanocomposites based on Polyhedral Oligomeric Silsesquioxanes PY - 2007 SN - 0743-0515 VL - 97 SP - 789 EP - 790 PB - Division of Polymeric Materials Science and Engineering, American Chemical Society CY - Washington, DC AN - OPUS4-15848 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Böhning, Martin A1 - Goering, Harald A1 - Hao, Ning A1 - Mach, Reinhard A1 - Schönhals, Andreas ED - Cassidy, P. T1 - Polycarbonate/SiC nanocomposites - Influence of nanoparticle dispersion on molecular mobility and gas transport T2 - 7th International Symposium on Polymers for Advanced Technologies CY - Fort Lauderdale, FL, USA DA - 2005-09-21 KW - Nanocomposites KW - Nanoparticles KW - Polycarbonates KW - Dielectric properties KW - Gas permeation PY - 2005 VL - 16 IS - 2-3 SP - 262 EP - 268 PB - Wiley CY - Chichester AN - OPUS4-7062 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Böhning, Martin A1 - Tidjani, Adams A1 - Wald, Oliver A1 - Turky, Gamal A1 - Goering, Harald A1 - Brzezinka, Klaus-Werner A1 - Schartel, Bernhard A1 - Schönhals, Andreas T1 - Polypropylene/Clay Nanocomposites - Gas Transport Characteristics and Molecular Mobility T2 - Polydays 2002 CY - Berlin, Germany DA - 2002-09-30 PY - 2002 SP - 1(?) EP - 2(?) AN - OPUS4-2038 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schönhals, Andreas T1 - Polycarbonate/SiC Nanocomposites - Influence of Nanoparticle Dispersion on Molecular Mobility and Gas Transport T2 - 7th International Symposium Polymers for Advanced Technologies CY - Fort Lauderdale, FL, USA DA - 2003-09-21 PY - 2003 AN - OPUS4-4650 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schönhals, Andreas T1 - Polycarbonate/SiC Nanocomposites - Influence of Nanoparticle Dispersion on Molecular mobility and Gas Transport T2 - 7th International Symposium Polymers for Advanced Technologies CY - Fort Lauderdale, FL, USA DA - 2003-09-21 PY - 2003 AN - OPUS4-4665 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schönhals, Andreas T1 - Gas Transport and Dielectric Relaxation in Polymer Based Nanocomposite Systems T2 - Vortrag Universität Lyon CY - Lyon, France DA - 2003-04-04 PY - 2003 AN - OPUS4-4060 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schönhals, Andreas T1 - Gas transport and dielectric relaxation in polymer based nanocomposite systems T2 - Vortrag Universität Lyon CY - Lyon, France DA - 2003-04-04 PY - 2003 AN - OPUS4-4112 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schönhals, Andreas T1 - Structure property relationships of different polymer based nanocomposites T2 - Frühjahrstagung der Deutschen Physikalischen Ges. / AKF, Condensed Matter CY - Dresden, Germany DA - 2006-03-26 PY - 2006 AN - OPUS4-11370 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schönhals, Andreas T1 - Structure-property relationsship of polymer based nanocomposites with polyhedral oligomeric silsesquioxanes as nanofillers T2 - Polydays 2006 CY - Berlin, Germany DA - 2006-10-04 PY - 2006 AN - OPUS4-13638 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Böhning, Martin A1 - Hao, Ning A1 - Schönhals, Andreas T1 - Gas transport and molecular mobility in polymer/POSS nanocomposites PY - 2006 DO - https://doi.org/10.1016/j.desal.2006.03.127 SN - 0011-9164 VL - 200 IS - 1-3 SP - 142 EP - 143 PB - Elsevier CY - Amsterdam AN - OPUS4-13707 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hao, N. A1 - Böhning, Martin A1 - Schönhals, Andreas T1 - CO2 gas transport properties of nanocomposites based on polyhedral oligomeric phenethyl-silsesquioxanes and poly(bisphenol A carbonate) N2 - Polymer-based nanocomposites were prepared by solution blending of polyhedral oligomeric silsesquioxane with phenethyl substituents (PhenethylPOSS) into poly(bisphenol A carbonate) (PBAC). First investigations focused on structure, morphology and dynamics, addressed mainly by dielectric relaxation spectroscopy are substantially extended in this study by the investigation of the CO2 gas transport behavior of these materials, i.e., permeation experiments using the time-lag technique as well as gravimetric gas sorption measurements. The nanocomposite materials were prepared with nanofiller contents ranging from 0 to about 40 wt % by solution blending and films of about 50-100 µm thickness were cast from this solution and used for the investigation of gas transport properties after drying and annealing. From the time-lag measurements the permeability and an effective diffusion coefficient for CO2 is obtained in dependence of POSS concentration and temperature. As main results, both, the permeability and the diffusivity, increase whereas the solubility decreases with increasing POSS concentration. These findings are discussed in the framework of a microphase separated morphology of the nanocomposite systems for POSS concentrations greater than a value cPOSScrit of ca. 7 wt % consisting of a polycarbonate-rich matrix and POSS-rich domains which are surrounded by an interfacial layer. The experimental solubility data suggest that the POSS-rich domains are more or less impermeable for CO2. On the basis of this assumption a quantitative model is provided to correct the solubility data for the phase separated morphology. Moreover the importance of the interfacial layer between the POSS particles or its domains for the properties of nanocomposites especially for the gas transport behavior is addressed by analyzing the sorption isotherms. Also, for the first time results from gas transport measurements and dielectric spectroscopy were quantitatively related to each other by taking the activation energies of CO2 diffusion and of the dielectric β-relaxation into consideration. The obtained clear correlation indicates that the CO2 gas transport is due to localized molecular fluctuations. As a further result, the diffusion coefficient obtained from time-lag and gas sorption measurements is in good agreement with respect to both their absolute values and in their concentration dependence. PY - 2010 DO - https://doi.org/10.1021/ma101463m SN - 0024-9297 SN - 1520-5835 VL - 43 IS - 22 SP - 9417 EP - 9425 PB - American Chemical Society CY - Washington, DC AN - OPUS4-22378 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Böhning, Martin A1 - Hao, Ning A1 - Schönhals, Andreas T1 - Correlation of activation energies of gas diffusivity and local matrix mobility in polycarbonate/POSS nanocomposites N2 - According to basic phenomenological models describing the solution-diffusion based mechanism of penetrant diffusion in dense polymers, a connection between the diffusive transport of gas molecules in a polymeric matrix and the molecular mobility of that matrix on a certain length scale is, in principle, established for a long time. However, experimental data directly showing this correlation are rare. The investigation of a series of nanocomposites based on a polyhedral oligomeric silsesquioxane (POSS) and a polycarbonate matrix allows a systematic change of the molecular mobility on a local length scale (β-relaxation) and of the corresponding activation energy EA, both determined by broadband dielectric spectroscopy. Independently, activation energies of penetrant diffusion (ED) of these nanocomposites were determined for N2, O2, CO2, and CH4 and a clear linear correlation between the two activation energies was established for the first time. KW - Broadband dielectric spectroscopy KW - Diffusion KW - Dielectric properties KW - Gas permeation KW - Molecular mobility KW - Nanocomposites KW - Polyhedral oligomeric silsesquioxane (POSS) KW - Relaxation KW - Beta-relaxation PY - 2013 UR - http://onlinelibrary.wiley.com/doi/10.1002/polb.23381/full DO - https://doi.org/10.1002/polb.23381 SN - 0887-6266 SN - 1099-0488 VL - 51 IS - 22 SP - 1593 EP - 1597 PB - Wiley CY - Hoboken, NJ AN - OPUS4-29284 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schönhals, Andreas T1 - Vibrational density of states and molecular mobility in a polymer with intrinsic microporosity PIM-1 as revealed by inelastic neutron scattering N2 - Polymers with intrinsic microporosity are promising candidates for the active separation layer in gas separation membranes. Here, by means of inelastic neutron scattering, the vibrational density of states (VDOS) and the molecular mobility were investigated for PIM-1, the prototypical polymer with intrinsic microporosity. The results are compared to data measured for a more conventional high-performance polyimide used in gas separation membranes (Matrimid). The measured data show the characteristic low frequency excess contribution to the VDOS above the Debye sound wave level, generally known as the Boson peak in glass-forming materials. In comparison to the Boson peak of Matrimid, that of PIM-1 is shifted to lower frequencies. This shift is discussed considering the microporous, sponge-like structure of PIM-1 as providing a higher compressibility at the molecular scale than for conventional polymers. Elastic fixed window scans were measured on a neutron backscattering spectrometer to have an overview about the molecular dynamics at a time scale of ca. 1 ns. The temperature dependence of the estimated mean squared displacement shows a step-like increase in the temperature range from 100 K to 250 K indicating the onset of some molecular mobility. The nature of this motional process was analyzed in detail by quasielastic neutron scattering where the data are discussed with regard to both the q- and the temperature dependence. T2 - QENS/WINWS 2018 CY - Hong Kong, China DA - 17.07.2018 KW - Polymers with intrinic microporosity KW - Quasielastic neutron scattering PY - 2018 AN - OPUS4-45534 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Konnertz, Nora A1 - Böhning, Martin A1 - Schönhals, Andreas T1 - Dielectric investigations of nanocomposites based on matrimid and polyhedral oligomeric phenethyl-silsesquioxanes (POSS) N2 - Matrimid and Matrimid/PhenethylPOSS nanocomposites films were prepared by solution casting. They can be considered as potential membrane materials for gas separation. Theire dielectric properties were investigated using Broadband Dielectric Spectroscopy (BDS) in combination with standard techniques. Matrimid shows one relaxation process assigned as beta*-relaxation and a conductivity contribution. The relaxation process has a high activation energy of 99 kJ/mol. Thus this process is supposed to be of cooperative nature due to a π-π stacking of the phenyl rings of Matrimid. The influence of the thermal history on Matrimid was analyzed with BDS as well where an annealing effect is found. The Matrimid/PhenethylPOSS nanocomposites show up to a concentration of about 4 wt% PhenethylPOSS a miscibility on a molecular level. For higher concentrations a phase separated structure was indicated. The conductivity of both systems is explained by π-π stacking of the phenyl rings which enhances charge transport. KW - Matrimid KW - POSS KW - Nanocomposites KW - Broadband dielectric spectroscopy PY - 2016 DO - https://doi.org/10.1016/j.polymer.2016.02.060 SN - 0032-3861 VL - 90 SP - 89 EP - 101 PB - Elsevier Science AN - OPUS4-35616 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Konnertz, Nora A1 - Ding, Yi A1 - Harrison, W.J. A1 - Budd, P.M. A1 - Schönhals, Andreas A1 - Böhning, Martin T1 - Molecular mobility and gas transport properties of nanocomposites based on PIM-1 and polyhedral oligomeric phenethyl-silsesquioxanes (POSS) N2 - Polymers with intrinsic microporosity (PIMs) are of great interest in the field of gas separation membranes. Already the first synthesized PIM-1 shows extraordinary permeability and selectivity. Unfortunately, PIM-1 is susceptible to physical aging and thus gradually loses its outstanding properties. In this study a polyhedral oligomeric silsesquioxane with phenethyl substituents (PhenethylPOSS) was used as a nanofiller (0–40 wt%) in the PIM-1 matrix to potentially improve the gas transport properties and prevent physical aging. The molecular mobility of the solution-cast nanocomposite films was analyzed by Broadband Dielectric Spectroscopy (BDS). Furthermore, gas permeability was determined with the time lag method (0–20 bar upstream pressure) at 35 °C for N2, O2, CH4 and CO2. KW - Broadband Dielectric Spectroscopy KW - Gas separation KW - Gas permeation KW - Polymers of intrinsic microporosity KW - Nanocomposite KW - POSS KW - PIM-1 PY - 2017 DO - https://doi.org/10.1016/j.memsci.2017.02.007 SN - 0376-7388 SN - 1873-3123 VL - 529 SP - 274 EP - 285 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-39169 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -