Transport Properties of Natural and Artificial Smart Fabrics Impregnated by Graphite Nanomaterial Stacks

none4noIn this work, we studied the transport properties (thermal and electrical conductivity) of smart fabric materials treated with graphite nanomaterial stacks–acetone suspensions. An innovative and easy method to produce graphite nanomaterial stacks–acetone-based formulations, starting from a low-cost expandable graphite, is proposed. An original, economical, fast, and easy method to increase the thermal and electrical conductivity of textile materials was also employed for the first time. The proposed method allows the impregnation of smart fabric materials, avoiding precoating of the fibers, thus reducing costs and processing time, while obtaining a great increase in the transport properties. Two kinds of textiles, cotton and Lycra®, were selected as they represent the most used natural and artificial fabrics, respectively. The impact of the dimensions of the produced graphite nanomaterial stacks–acetone-based suspensions on both the uniformity of the treatment and the transport properties of the selected textile materials was accurately evaluated using several experimental techniques. An empirical relationship between the two transport properties was also successfully identified. Finally, several theoretical models were applied to predict the transport properties of the developed smart fabric materials, evidencing a good agreement with the experimental data.openCarola Esposito Corcione; Francesca Ferrari; Raffaella Striani; Antonio GrecoESPOSITO CORCIONE, Carola; Ferrari, Francesca; Striani, Raffaella; Greco, ANTONIO STEFAN

An Innovative Method for the Recycling of Waste Carbohydrate Based Flours

This work represents an innovative study that, for the first time, explores the possibility to use waste flours to produce thermoplastic polymeric bio-films. To the best of our knowledge, this is the first time that waste flours, derived from bakeries, pizzerias or pasta factories, have been proposed for the production of bio-polymers, as a replacement of neat starch. To this aim, durum waste flour derived from a pasta factory, soft waste flour derived from pizzerias and neat maize starch used as control material were firstly analyzed from dimensional, morphological and chemical points of view. Afterwards, waste flour films were produced by the addition of a nature-based plasticizer, glycerol. Mechanical characterization of the plasticized thermoplastic films, produced by compression molding, evidenced low performances, even in the case of the neat maize starch. In order to improve the mechanical properties, the possibility to include polylactic acid and cardanol based plasticizer was also investigated. Mass transport properties of all the produced bio-films were investigated by measuring their water vapor permeability and hygroscopic absorption. The durability properties of the bio-films were assessed by accelerated ageing tests, while the biodegradability of the waste-based films was evaluated by measuring the solubility and the degradation in water. The physicochemical analyses of the novel bio-films evidenced good mechanical properties; specifically, the waste-based films showed a lower hygroscopic absorption and water solubility than those of the blends containing neat starch

valorization of food industries wastes for the production of poly vinyl alcohol pva biodegradable composites

This work is aimed to the development of new green composite materials by the incorporation of natural additives into poly(vinyl) alcohol (PVA). Two additives, shredded walnut shells and organic fraction of municipal solid waste (MW), were used to improve the mechanical properties of PVA. Both additives, derived from food industry wastes, were added in a PVA/water solution, which allowed to produce samples by the use of a pressure free process. Rheological analysis was performed in order to study the evolution of the material viscosity during thermal treatment, aimed at water removal. Samples obtained were characterized by means of differential scanning calorimetry (DSC), showing an improvement of the glass transition temperature brought by the addition of walnut shells. Finally, flexural tests were carried out on samples obtained after the incorporation of the different additives in PVA and compared with the mechanical properties of the neat matrix. Results obtained indicate the potential improvement brought by the addition of walnut shells, which allows increasing the flexural modulus of about 50%, at the expenses of a flexural strength reduction of about 30%. Also, at least for low amount of added water, the addition of MW was shown to provide an increase of the strain at break equal to 100%

Real-life experience with ceftobiprole in a tertiary-care hospital

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Effect of multi-scale diffusion on the permeability behavior of intercalated nanocomposites

Abstract This paper is aimed to study the morphology of intercalated nanocomposites, by coupling experimental permeability data with different analytical models. X-Ray diffraction provided the reference morphological features of the nanocomposite, including gallery thickness and aspect ratio of the lamellar stacks. Afterward, the water permeability of two intercalated nanocomposites was used for the calculation of the nanofiller aspect ratio, following different approaches. The obtained results indicate that an assumption of impermeable stacks involves a significant over- estimation of the nanofiller aspect ratio. Further, when the morphological features determined in the assumption of impermeable particles are used for estimation of the nanocomposite diffusivity by the use of the Fricke model, results do not show a satisfactory agreement with experimental data. On the other hand, fitting experimental permeability data with an analytical model accounting for intra-stack diffusion provided an estimation of the nanofiller aspect ratio in excellent agreement with that obtained by XRD. Further, applying the Fricke equation with the morphological features determined by the permeable stack model, an excellent agreement to the experimental data was obtained. The results indicate the relevance of intra-stack diffusion in intercalated nanocomposite, and the need to account for it when modeling mass transfer in nanocomposites

Clay-nanocomposites polyurethane adhesives: Analysis of the rigid amorphous fraction

In this work nanocomposite adhesives for flexible packaging obtained using an organically modified montmorillonite (OMM) in a polyurethane matrix were synthesized and characterized. The microstructure of the composites was investigated by X-ray diffraction. The glass transition temperature of PU nanocomposites, measured using differential scanning calorimeter, increases with increasing volume fraction of OMM. On the other hand, the specifc heat increment, ΔCP, normalized to the weight of the organic fraction, decreases as nanoclay was added. Therefore a corresponding increase of the rigid amorphous fraction of PU nanocomposites with nanoclay was observed

The aspect ratio of nanofillers:A key properties affecting the performances of polymer matrix nanocomposites

The engineering aspects associated with nanocomposite development are strongly dependent on the final properties that can be achieved as well as on their processability. Both features are affected by the average distribution of nanofiller in the matrix, or in other words by its dispersion. Furthermore, characterization of intercalation or exfoliation of organic modified montmorillonite (omMMT) or graphene lamellae by X-ray or transmission electron microscopy cannot be easily related to nanocomposite macroscopic properties (mechanical, rheological etc.), the most relevant from an engineering point of view. On the other hand mechanical and rheological analysis shows that properties of nanocomposites are not only dependent from lamellar spacing but also the aspect ratio plays a key role. Even if single graphene sheets or single omMMT are not observed in the matrix bulk, a high aspect ratio of the filler can generate a significant improvement of macroscopic properties. Finally, the measurements of engineering properties of nanocomposites not only represent an objective but can provide information about the average degree of dispersion. Comparison of mechanical and rheological properties with simple mathematical models can be used to determine the average aspect ratio of nanofillers. It may be concluded that macrocharacterization can represent a valuable and complementary tool for the morphological characterization of nanocomposites being capable of providing information about the level of dispersion of nanocomposites