Cellulosic materials as natural fillers in starch-containing matrix-based films: a review

In this work, the different cellulosic materials, namely cellulose and lignin are analyzed. In addition, the starch-containing matrices (isolated starch and flour) reinforced with cellulosic materials to be used in packaging applications are described. Many efforts have been exerted to develop biopackaging based on renewable polymers, since these could reduce the environmental impact caused by petrochemical resources. Special attention has had the starch as macromolecule for forming biodegradable packaging. For these reasons, shall also be subject of this review the effect of each type of cellulosic material on the starch-containing matrix-based thermoplastic materials. In this manner, this review contains a description of films based on starch-containing matrices and biocomposites, and then has a review of cellulosic material-based fillers. In the same way, this review contains an analysis of the works carried out on starch-containing matrices reinforced with cellulose and lignin. Finally, the manufacturing processes of starch/cellulose composites are provided as well as the conclusions and the outlook for future works.Fil: Gutiérrez Carmona, Tomy José. Universidad Central de Venezuela; Venezuela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Alvarez, Vera Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin

Advances in magnetic noble metal/iron-based oxide hybrid nanoparticles as biomedical devices

The study of the noble metal magnetic hybrid nanoparticles is a really promising topic from both the scientific and the technological points of views, with applications in several fields. Iron oxide materials which are hybridized with noble metal nanoparticles (NPs) have attracted increasing interest among researchers because of their cooperative effects on combined magnetic, electronic, photonic, and catalytic activities. This review article contains a summary of magnetic noble metal/iron oxide nanoparticle systems potentially useful in practical biomedical applications. Among the applications, engineered devices for both medical diagnosis and treatments were considered. The preparation to produce different structures, as blends or core-shell structures, of several nanometric systems was also considered. Several characterization techniques available to describe the structure, morphology and different kinds of properties of hybrid nanoparticles are also included in this review.Fil: Sanchez, Laura Mabel. Universidad Nacional de Mar del Plata; ArgentinaFil: Alvarez, Vera Alejandra. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin

Bionanocomposite films developed from corn starch and natural and modified nano-clays with or without added blueberry extract

Edible and bionanocomposite films were developed by extrusion followed by thermo molding. Corn starch (Zea mays), glycerol, and several nano-clays were used as the carbohydrate polymer, plasticizer and nano-fillers, respectively. Pure blueberry (Vaccinium corymbosum) extract (BE, 100% anthocyanin), as well as natural and modified montmorillonites (Mnt) with or without BE nano-packaged within their layers were incorporated into the thermoplastic starch (TPS) matrix. Previous studies by our research group have shown that BE, and BE nano-packaged within natural and modified Mnt, are pH-sensitive. With this in mind, we set out to develop edible and intelligent (pH-sensitive) bionanocomposite films with improved properties. Unfortunately however, none of the films formulated were pH-sensitive. All the films showed X-ray diffractograms typical of semicrystalline, albeit largely amorphous, materials coinciding with the morphological observations made under scanning electron microscopy. The results confirmed that total starch gelatinization occurred under the selected extrusion conditions. Films prepared from corn starch containing BE showed a plasticizing effect, giving materials with lower thermal resistance and surface moisture values, which were also more opaque, denser, and rougher. All the nano-fillers tested were completely exfoliated within the TPS matrix, except for the natural Mnt that was partly exfoliated and partly intercalated in the matrix. In general, materials containing nano-fillers with a greater degree of interlayer spacing (more exfoliated) showed higher thermal resistance and Young's modulus, but lower strain at break values.Fil: Gutiérrez Carmona, Tomy José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Alvarez, Vera Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin

Functionalization, compatibilization and properties of polyolefin composites with natural fibers

The article is focused on analyzing the effect of functionalization and reactive processing on the morphological, thermal, rheological and mechanical properties of composites of isotactic polypropylene (PP), polystyrene (PS), poly(ethylene-vinyl acetate) (EVA), with cellulose fibers, hemp or oat as natural fillers. Both polymers and fibers were modified with bi-functional monomers (glycidyl methacrylate, GMA; maleic anhydride, MA) capable of facilitating chemical reactions between the components during melt mixing. Polyolefin copolymers containing reactive groups (PP-g-GMA, SEBS-g-MA, PS-co-MA, etc.) were used as compatibilizers. Optical and SEM microscopy, FTIR, RX, DSC, TGA, DMTA, rheological and mechanical tests were employed for the composites characterization. The properties of binary and ternary systems have been analyzed as a function of both fiber and compatibilizer content. All compatibilized systems showed enhanced fiber dispersion and interfacial adhesion. The phase behavior and the thermal stability of the composites were affected by the chemical modification of the fibers. Marked changes in the overall crystallization processes and crystal morphology of PP composites were observed owing to the nucleating effect of the fibers. The tensile mechanical behavior of the compatibilized composites generally resulted in a higher stiffness, depending on the fiber amount and the structure and concentration of compatibilizer.Fil: Pracella, Mariano. Institute of Composite and Biomedical Materials; ItaliaFil: Minhaz-Ul Haque, M.. Universita Degli Studi Di Pisa; ItaliaFil: Alvarez, Vera Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación en Ciencia y Tecnología de Materiales (i); Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería; Argentin

Optimization of Acid Hydrolysis Process for the Preparation Cellulose Nanofibrils

Cellulose nanofibrils can be obtained from microcrystalline cellulose by acid hydrolysis processes. Under optimum hydrolysis conditions is possible to obtain cellulose nanofibers with high surface / volume ratio, high aspect ratio (length to diameter), high crystallinity and improved thermal stability. All these parameters then determine their effectiveness as reinforcement in a polymer matrix. In this work, cellulose nanofibrils were obtained from commercial microcellulose supplied by Aldrich. The acid hydrolysis synthesis was optimized studying the effect of reaction time and temperature and acid solution concentration. The optimized parameters were selected so as to obtain fibers with high crystallinity, high aspect ratio with diameter in nanoscale and high thermal stability. The morphology and size (length and diameter) of the fibers was analyzed by Field Emission Scanning Electron Microscopy (FESEM), the chemical structure by Fourier Transform Infrared Spectroscopy (FTIR), thermal stability by Thermogravimetric Analysis (TGA) and crystallinity by X-ray Diffraction (XRD).Fil: Bracone, Melina Ethel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Ludueña, Leandro Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Alvarez, Vera Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin

Mycosinthetized Ag, CuO and ZnO nanoparticles from a promising Trichoderma harzianum strain and their antifungal potential against important phytopathogens

Fungal green biosynthesis of nanoparticles (NPs) is a promising eco-friendly method for mass-scale production. In the present study Ag, CuO and ZnO nanoparticles were biogenically synthetized using a cell filtrate of a strain of Trichoderma harzianum as a reducer and stabilizer agent. The structure, morphology and physicochemical properties of the NPs were characterized through transmission electron microscopy, dynamic light scattering, wide angle X-ray scattering and thermogravimetric analysis. Since nanotechnology could offer promising applications in agricultural area, we evaluated the ability of the NPs to reduce the growth of important fungal phytopathogens as Alternaria alternata, Pyricularia oryzae and Sclerotinia sclerotiorum. Silver and CuO NPs reduced significantly the mycelial growth of A. alternata and P. oryzae in a dose dependent manner. This is the first report of a multiple extracellular biosynthesis of NPs from T. harzianum and the first time that CuO and ZnO NPs were obtained from this fungus. In addition, we highlighted the rapid production of NPs, as well as, the potential of Ag and CuO for the control of phytopathogens. On the other hand, the three types of NPs could be easily and sustainably produced on a large scale with the chance of having multiple applications in biotechnological processes.Fil: Consolo, Verónica Fabiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología; Argentina. Fundación para Investigaciones Biológicas Aplicadas; ArgentinaFil: Torres Nicolini, Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Alvarez, Vera Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin

Microencapsulation of epoxy resins: Optimization of synthesis conditions

In this work, a series of microcapsules were prepared by in situ polymerization in oil-in-water emulsion with poly(urea-formaldehyde) as shell material and diglycidyl ether of bisphenol F as core substance. Different reaction parameters were analyzed: emulsification conditions (time, agitation method and rate), the viscosity of the core phase, stirring speed during synthesis, core/shell mass ratio and drying process. Morphology, chemical structure, mean size, size distribution and thermal properties of the resulting microcapsules were studied by Scanning Electron Microscopy (SEM) and Optical Microscopy (OM), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC). Several spherical microcapsules with different sizes and distributions were obtained by the adjustment of reaction parameters. Lyophilized microcapsules resulted in free flowing powders, which remained stable under more than 1 year at ambient laboratory conditions. From preliminary testing results, it was demonstrated that microcapsules fabricated under optimized reaction conditions had a satisfactory size and shell structure and were strong enough to bear the manufacturing of an epoxy-based composite material. Thus, results obtained in this work show that these microcapsules are potential candidates for the development of self-healing composites.Fil: Ollier Primiano, Romina Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Penoff, Marcela Elisabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Alvarez, Vera Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin

Effect of relative humidity on the mechanical properties of micro and nanocomposites of polyvinyl alcohol

The effect of relative humidity on the mechanical properties of poly(vinyl alcohol) (PVOH) micro and nanocomposites was evaluated. Two different commercial fillers (microcellulose and bentonite) were used as reinforcement. PVOH and PVOH composite films were prepared by casting technique. The incorporation of microcellulose increased the content of water absorption and the modulus, especially for the higher contents of filler. The effect of reinforcement on the mechanical properties was more pronounced at higher relative humidity. On the other hand, the incorporation of nanofiller produced a decrease in water absorption probably due to the decrease of mean free path of water molecules. The modulus of the nanocomposites improved from the matrix, but the mechanical properties are deteriorated by effect of the humidity.Fil: Ollier Primiano, Romina Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación en Ciencia y Tecnología de Materiales (i); Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería; ArgentinaFil: Pérez, Claudio Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación en Ciencia y Tecnología de Materiales (i); Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería; ArgentinaFil: Alvarez, Vera Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación en Ciencia y Tecnología de Materiales (i); Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería; Argentin

Composite Gels Based on Poly (Vinyl alcohol) for Biomedical Uses

Nowadays, poly (vinyl alcohol) (PVA) hydrogels are being studied for several biomedical applications such as joint replacement, wound dressings and controlled drug-releasing devices, among others. Reinforced PVA hydrogels show good mechanical properties and are a suitable option to replace cartilages. Furthermore, these materials can prevent loss of body fluids, be a barrier against bacteria and also permeable to oxygen, for these all interesting properties, they are used like wound dressings. For drug delivery systems a material that can control the dose and release at the site of action is desirable, this can be accomplished using hydrogels, which are loaded with a drug, and then they can release it when an external stimulus (light, temperature, magnetic field, etc.) takes place. The aim of this work was to obtain composite hydrogels for the previously mentioned biomedical applications. Hydroxyapatite (HA) reinforced PVA gels were prepared for potential uses as cartilage replacement, HA improves the mechanical, tribological and fixing properties of the polymer, reaching values similar to that of the cartilages. For wound dressings, the hydrogel was reinforced with bentonite (clay) in order to increase the dimensional stability and antimicrobial properties. Gels with controlled drug release capability under magnetic stimulation (ferrogels) were also synthesized and characterized here.Fil: Hoppe, Cristina Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación en Ciencia y Tecnología de Materiales (i); ArgentinaFil: Alvarez, Vera Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación en Ciencia y Tecnología de Materiales (i); ArgentinaFil: Maiolo, Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación en Ciencia y Tecnología de Materiales (i); ArgentinaFil: Gonzalez, Jimena Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación en Ciencia y Tecnología de Materiales (i); Argentin

Manufacturing and testing of a sandwich panel honeycomb core reinforced with natural-fiber fabrics

A novel honeycomb core made of a natural-fiber reinforced composite consisting of a vinylester matrix reinforced with jute fabric is introduced. Six-mm- and 10-mm-cell honeycombs are manufactured using two compression-molding techniques. Best results are obtained for the mold with lateral compression. Experimental tests are conducted to characterize the elastic response of the composite and the core response under flatwise compression. The effective elastic properties of the core are computed via a homogenization analysis and finite element modeling. The results of the homogenization analysis are in very good agreement with estimations done using analytical formulas from the bibliography. The flatwise compression tests show that the core failure mechanisms are yarn pull-out and fiber breaking. The large wall thickness relative to the cell size of the jute-vinylester cores, which inhibits buckling, and the heterogeneities in the composite, which are preferential damage initiation sites, explain the observed behavior. When compared in terms of the specific strengths, the jute/vinylester cores introduced in this work show similar performances to those of their commercially available counterparts. The results from this study suggest that jute-reinforced cores have the potential to be an alternative to standard cores in applications that sustain compressive static loads.Fil: Stocchi, Ariel Leonardo. Universidad Nacional de Mar del Plata. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación en Ciencia y Tecnología de Materiales (i); ArgentinaFil: Colabella, Lucas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación en Ciencia y Tecnología de Materiales (i); ArgentinaFil: Cisilino, Adrian Pablo. Universidad Nacional de Mar del Plata. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación en Ciencia y Tecnología de Materiales (i); ArgentinaFil: Alvarez, Vera Alejandra. Universidad Nacional de Mar del Plata. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación en Ciencia y Tecnología de Materiales (i); Argentin