Sustainable Sheep Wool/Soy Protein Biocomposites for Sound Absorption.

The wool fibers of the Latxa sheep breed were combined with a soy protein isolate (SPI) matrix to develop sustainable biocomposites with acoustic properties, adding value to Latxa sheep wool, which is currently considered a residue. Samples with 7, 10, 15, and 20 wt % wool were prepared by freeze drying in order to develop porous structures, as shown by SEM analysis. Additionally, XRD analysis provided the evidence of a change toward a more amorphous structure with the incorporation of wool fibers due to the interactions between the soy protein and keratin present in wool fibers, as shown by the relative intensity changes in the FTIR bands. The biocomposites were analyzed in a Kundt's tube to obtain their sound absorption coefficient at normal incidence. The results showed an acoustic absorption coefficient that well-surpassed 0.9 for frequencies above 1000 Hz. This performance is comparable to that of the conventional synthetic materials present in the market and, thus, sheep wool/SPI biocomposites are suitable to be used as acoustic absorbers in the building industry, highlighting the potential of replacing not only synthetic fibers but also synthetic polymers, with natural materials to enhance the sustainability of the building sector.

Optimizing the extraction process of natural antioxidants from chardonnay grape marc using microwave-assisted extraction.

The aim of this work was to extract phenolic compounds from Chardonnay grape marc employing a microwave-assisted extraction (MAE). Firstly, the effect of solvent concentration (30-60%), solid mass (1.0-2.0 g) and extraction time (5-15 min) on the recovery of phenolic content and antioxidant capacity was evaluated using a response surface methodology (RSM). The optimal parameters found by RSM were 48% ethanol for the solvent content, 10 min for the extraction time, and 1.77 g for the solid mass. The extraction was carried out at room temperature to increase scaling-up opportunities at industrial level. It was found that the phenolic profile was mainly composed of flavanols, such as procyanidins, catechin and epicatechin. Furthermore, the polyphenols obtained by MAE showed a DPPH· inhibition value of 87 ±â€¯5% and the total phenolic content was 1.21 ±â€¯0.04 mg GAE/mL. Finally, it was observed that the degradation temperature of the extract (≈ 200 °C) was above the temperature commonly used for the manufacture of protein films by thermo-mechanical processes. This highlights the potential use of this extract as a bioactive additive in protein film forming formulations for food and pharmaceutical applications.

Assessment of gallic acid-modified fish gelatin formulations to optimize the mechanical performance of films.

In this study, a response surface methodology (RSM) using a Box-Behnken design was applied to optimize the mechanical response (tensile strength, elongation at break and Young's modulus) of fish gelatin films. These responses were analyzed as a function of glycerol content (0-10% on gelatin basis), added as a plasticizer, gallic acid content (5-15% on gelatin basis), used as crosslinker, and solution pH (4.5-10). Second order polynomial models were adjusted for the three responses, and they were found to be reliable according to the standard statistical analysis. The values of the independent factors that maximize the responses were also determined. In order to relate mechanical performance to material structure, Fourier transform infrared (FTIR) analysis was carried out and this revealed that a reaction occurs between gelatin and gallic acid through a process that releases water and provides a plasticizing effect. The performed time-, material- and cost-saving optimization of the formulation based on biodegradable compounds from abundant renewable resources enabled a sustainable approach to the development of new materials.

Optimization of solution-processed oligothiophene:fullerene based organic solar cells by using solvent additives.

The optimization of solution-processed organic bulk-heterojunction solar cells with the acceptor-substituted quinquethiophene DCV5T-Bu 4 as donor in conjunction with PC61BM as acceptor is described. Power conversion efficiencies up to 3.0% and external quantum efficiencies up to 40% were obtained through the use of 1-chloronaphthalene as solvent additive in the fabrication of the photovoltaic devices. Furthermore, atomic force microscopy investigations of the photoactive layer gave insight into the distribution of donor and acceptor within the blend. The unique combination of solubility and thermal stability of DCV5T-Bu 4 also allows for fabrication of organic solar cells by vacuum deposition. Thus, we were able to perform a rare comparison of the device characteristics of the solution-processed DCV5T-Bu 4 :PC61BM solar cell with its vacuum-processed DCV5T-Bu 4 :C60 counterpart. Interestingly in this case, the efficiencies of the small-molecule organic solar cells prepared by using solution techniques are approaching those fabricated by using vacuum technology. This result is significant as vacuum-processed devices typically display much better performances in photovoltaic cells.

Linear and star-shaped naphthalimide-fused pyrazinacenes.

A novel naphthalimide derivative endowed with a diketone functionality has been synthesized and used to develop a family of highly symmetric, flat, n-type semiconducting naphthalimide-based pyrazinacenes. By changing the symmetry of these compounds and the number of naphthalimide constituents, fine tuning of their electrochemical, photophysical, and morphological properties is achieved.

STM study on the self-assembly of oligothiophene-based organic semiconductors.

The self-assembly properties of a series of functionalized regioregular oligo(3-alkylthiophenes) were investigated by using scanning tunneling microscopy (STM) at the liquid-solid interface under ambient conditions. The characteristics of the 2-D crystals formed on the (0001) plane of highly ordered pyrolitic graphite (HOPG) strongly depend on the length of the π-conjugated oligomer backbone, on the functional groups attached to it, and on the alkyl substitution pattern on the individual thiophene units. Theoretical calculations were performed to analyze the geometry and electronic density of the molecular orbitals as well as to analyze the intermolecular interactions, in order to obtain models of the 2-D molecular ordering on the substrate.