Synthesis of bio-polyol-functionalized nanocrystalline celluloses as reactive/reinforcing components in bio-based polyurethane foams by homogeneous environment modification.

Nanocrystalline Cellulose (NCC or CNC) is widely used as a filler in polymer composites due to its high specific strength, tensile modulus, aspect ratio, and sustainability. However, CNC hydrophilicity complicates its dispersion in hydrophobic polymeric matrices giving rise to aggregate structures and thus compromising its reinforcing action. CNC functionalization in a homogeneous environment, through silanization with trichloro(butyl)silane as a coupling agent and subsequent grafting with bio-based polyols, is herein investigated aiming to enhance CNC dispersibility improving the filler-matrix interaction between the hydrophobic PU and hydrophilic CNC.

Chemically Functionalized Cellulose Nanocrystals as Reactive Filler in Bio-Based Polyurethane Foams.

Cellulose Nanocrystals, CNC, opportunely functionalized are proposed as reactive fillers in bio-based flexible polyurethane foams to improve, mainly, their mechanical properties. To overcome the cellulose hydrophilicity, CNC was functionalized on its surface by linking covalently a suitable bio-based polyol to obtain a grafted-CNC. The polyols grafted with CNC will react with the isocyanate in the preparation of the polyurethane foams.

On the influence of multiple cations on the in-gap states and phototransport properties of iodide-based halide perovskites.

In-gap states in solar cell absorbers that are recombination centers determine the cell's photovoltaic performance. Using scanning tunneling spectroscopy (STS), temperature-dependent photoconductivity and steady-state photocarrier-grating measurements we probed, directly and indirectly, the energies of such states, both at the surface and in the bulk of two similar, but different halide perovskites, the single cation MAPbI (here MAPI) and the mixed cation halide perovskite, FAMACsPb(IBr) (here MCHP). We found a correlation between the energy distribution of the in-gap states, as determined by STS measurements, and their manifestation in the photo-transport parameters of the MCHP absorbers.

Multivalency as a key factor for high activity of selective supported organocatalysts for the Baylis-Hillman reaction.

The polystyrene-supported N-alkylimidazole-based dendritic catalysts for the Baylis-Hillman reaction exhibit one of the strongest beneficial effects of multivalent architecture ever reported for an organocatalyst. The yields in the model reaction of methyl vinyl ketone with p-nitrobenzaldehyde are more than tripled when a non-dendritic catalyst is replaced by a second- or third-generation analogue. Moreover, the reaction of the less active substrates will not occur with the non-dendritic catalyst and will proceed to a significant extent only with the analogous catalysts of higher generations.