Microscopic versus Macroscopic Glass Transitions and Relevant Length Scales in Mixtures of Industrial Interest.

We have combined X-ray diffraction, neutron diffraction with polarization analysis, small-angle neutron scattering (SANS), neutron elastic fixed window scans (EFWS), and differential scanning calorimetry (DSC) to investigate polymeric blends of industrial interest composed by isotopically labeled styrene-butadiene rubber (SBR) and polystyrene (PS) oligomers of size smaller than the Kuhn length. The EFWS are sensitive to the onset of liquid-like motions across the calorimetric glass transition, allowing the selective determination of the "microscopic" effective glass transitions of the components. These are compared with the "macroscopic" counterparts disentangled by the analysis of the DSC results in terms of a model based on the effects of thermally driven concentration fluctuations and self-concentration.

Disentangling the Calorimetric Glass-Transition Trace in Polymer/Oligomer Mixtures from the Modeling of Dielectric Relaxation and the Input of Small-Angle Neutron Scattering.

We have disentangled the contributions to the glass transition as observed by differential scanning calorimetry (DSC) on simplified systems of industrial interest consisting of blends of styrene-butadiene rubber (SBR) and polystyrene (PS) oligomer. To do this, we have started from a model previously proposed to describe the effects of blending on the equilibrium dynamics of the α-relaxation as monitored by broadband dielectric spectroscopy (BDS). This model is based on the combination of self-concentration and thermally driven concentration fluctuations (TCFs).

Photolabile Well-Defined Polystyrene Grafted on Silica Nanoparticle via Nitroxide-Mediated Polymerization (NMP).

Herein, the synthesis of a novel nitroxide-mediated polymerization (NMP) initiator bearing a photolabile ortho-nitrobenzyl (oNB) group allowing surface-initiated NMP preparation of well-defined photoresponsive polystyrene grafted on silica nanoparticles is described. The photocleavable and photoresponsive properties of the prepared materials are demonstrated using small angle X-ray scattering (SAXS) characterization.

Cobalt-Iron-Manganese Catalysts for the Conversion of End-of-Life-Tire-Derived Syngas into Light Terminal Olefins.

Co-Fe-Mn/γ-Al O Fischer-Tropsch synthesis (FTS) catalysts were synthesized, characterized and tested for CO hydrogenation, mimicking end-of-life-tire (ELT)-derived syngas. It was found that an increase of C -C olefin selectivities to 49 % could be reached for 5 wt % Co, 5 wt % Fe, 2.5 wt % Mn/γ-Al O with Na at ambient pressure.

Multiplex MQMAS NMR of quadrupolar nuclei.

A multiplex phase cycling method (N. Ivchenko et al., J.

NO2 disproportionation for the IR characterisation of basic zeolites.

NO2 disproportionation on alkaline zeolites is used to generate nitrosonium (NO+) and nitrate ions on the surface, and the infrared vibrations observed are very sensitive to the cation chemical hardness and to the basicity of zeolitic oxygen atoms.