Dresden 2011 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 43: Nanoparticles and Composite Materials I
CPP 43.3: Talk
Thursday, March 17, 2011, 14:45–15:00, ZEU 222
Structure Property Relationships of Nanocomposites based on Polypropylene and Layered Double Hydroxide — •Purv Purohit, Jesus Sanchez, and Andreas Schönhals — BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, 12205 Berlin, Germany
Nanocomposites based on Polypropylene (PP) and modified ZnAl Layered Double Hydroxides (ZnAl-LDH) were prepared and investigated by a combination of differential scanning calorimetry (DSC), Small and Wide angle X-ray scattering (SAXS & WAXS) and Dielectric Relaxation Spectroscopy. Space resolved SAXS investigation show that the samples are homogeneous on a length scale of several cm and have a predominantly exfoliated morphology. DSC and WAXS show that the degree of crystallinity decreases with the increasing content of LDH. The extrapolation of this dependence to zero estimates a limiting concentration of c.a. 40% LDH where the crystallization of PP is completely suppressed. The dielectric response of the nanocomposites shows several relaxation processes. The intensity of the dynamic glass transition increases with the concentration of LDH. This is attributed to the increasing concentration of the exchanged anion dodecylbenzene sulfonate (SDBS), which are adsorbed at the LDH layers. Therefore, analysis of the beta-relaxation provides information about the interfacial region between the LDH layers and the PP matrix. The glass transition temperature in this interfacial region is by 30 K lower than that of PP. This is accompanied by a change of the fragility deduced from the relaxation map.