TY - JOUR A1 - Hao, Ning A1 - Böhning, Martin A1 - Wohlrab, Sebastian A1 - Schönhals, Andreas T1 - Polymer Based Nanocomposites with PhenethylPOSS as Nanofilter Investigated by Dielectric Spectroscopy and Gas Transport Measurements N2 - Polyhedral oligomeric silsesquioxane with phenethyl substituents (PhenethylPOSS) as nanofiller was incorporated within Poly(bisphenol A carbonate) (PBAC) as matrix. Dielectric spectroscopy proved an almost complete miscibility of PhenethylPOSS up to 7 wt. %. At higher concentrations phase separation yields composites with a PBAC-rich matrix and POSS-rich domains which posses well shaped interfaces. The nanocomposites were also investigated with respect to their gas transport behaviour. An increase of the gas permeability was found at higher PhenethylPOSS concentrations, which is due to the phase separated structure. KW - Dielectric measurements KW - Nanocomposites KW - Permeation KW - Polycarbonates KW - Polyhedral oligomeric silsesquioxanes PY - 2008 DO - https://doi.org/10.1002/masy.200850712 SN - 1022-1360 SN - 0258-0322 SN - 1521-3900 VL - 267 IS - 1 SP - 69 EP - 73 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-17751 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hao, Ning T1 - Molecular Mobility and Gas Transport Properties of Polycarbonate-based Nanocomposites T2 - Workshop Glasübergang CY - Berlin, Germany DA - 2003-12-14 PY - 2003 AN - OPUS4-4198 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hao, Ning A1 - Böhning, Martin A1 - Goering, Harald A1 - Schönhals, Andreas T1 - Nanocomposites of Polyhedral Oligomeric Phenethylsilsesquioxanes and Poly(bisphenol A carbonate) as Investigated by Dielectric Spectroscopy N2 - Nanocomposites were prepared by solution blending of polyhedral oligomeric silsesquioxane with phenethyl substituents (PhenethylPOSS) into poly(bisphenol A carbonate) (PBAC). The nanocomposites were investigated by dielectric spectroscopy, differential scanning calorimetry (DSC) and density measurements. PhenethylPOSS shows one relaxation process, the α-relaxation, confirmed by DSC investigations. PBAC shows a β-relaxation at lower and an α-relaxation at higher temperatures. With increasing PhenethylPOSS content the α-relaxation of the composites shifts to lower temperatures. Thus, incorporation of PhenethylPOSS leads to a plasticization of PBAC due to a decrease of the packing density which is rationalized by density measurements. For higher concentrations of PhenethylPOSS (>10 wt %) the α-relaxation of the polycarbonate matrix splits into two peaks. Moreover, close to the α-relaxation of PhenethylPOSS a third process is observed. These results indicate a phase separation into a PBAC matrix with a few percents of molecularly solved POSS and POSS-rich domains. These POSS-rich domains are surrounded by an interfacial layer of PBAC having a higher concentration of POSS than the matrix. A phase diagram is deduced providing a miscibility criterion. For the phase separated nanocomposites an interfacial polarization phenomena is observed. Using a simplified model the time constant of this process is correlated with the size of the PhenethylPOSS-rich domains and theire increasing size with the increase of the concentration of POSS. KW - Polyhedral oligomeric silsesquioxane (POSS) KW - Polymer-based nanocomposites KW - Broadband dielectric spectroscopy KW - Interfacial polarisation PY - 2007 SN - 0024-9297 SN - 1520-5835 VL - 40 IS - 8 SP - 2955 EP - 2964 PB - American Chemical Society CY - Washington, DC AN - OPUS4-14768 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hao, Ning A1 - Böhning, Martin A1 - Schönhals, Andreas T1 - Gas Transport Properties of Polymeric Nanocomposites Based on Polyhedral Oligomeric Silsesquioxanes PY - 2007 SN - 0743-0515 VL - 97 SP - 444 EP - 445 PB - Division of Polymeric Materials Science and Engineering, American Chemical Society CY - Washington, DC AN - OPUS4-15846 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Böhning, Martin A1 - Goering, Harald A1 - Hao, Ning A1 - Mach, Reinhard A1 - Oleszak, Franz A1 - Schönhals, Andreas T1 - Molecular Mobility and Gas Transport Properties of Polycarbonate-Based Nanocomposites PY - 2003 UR - http://www.ipme.ru/e-journals/RAMS/no_3503/bohning/bohning.html SN - 1606-5131 VL - 5 SP - 155 EP - 159 PB - Advanced Study Center CY - St. Petersburg AN - OPUS4-2884 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Goering, Harald A1 - Böhning, Martin A1 - Turky, Gamal A1 - Hao, Ning A1 - Schönhals, Andreas T1 - Molecular Dynamics in Polymer Nanocomposites T2 - Workshop "Glasübergang" CY - Rostock, Germany DA - 2002-12-16 PY - 2002 AN - OPUS4-2061 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - 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 - 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 -