1,721,150 research outputs found
Biomimetic multifunctional materials: a review
No full textInspired from nature, material scientists design and fabricate fascinating multifunctional composites for various applications. The profound insight on hierarchical micro/nanostructures or biological functions behind biomimetic properties and functions and their proper integration in a material for specific applications are crucial in developing biomimetic multifunctional composites. The current review discusses in detail the integration of potentially relevant biomimetic properties and/or functions such as self-cleaning with anti-reflection, self-cleaning with anti-corrosion, self-healing with self-cleaning, shape memory and wettability, super strong and tough, and self-healing with super tough. This review also outlines potential applications of such multifunctional composites in biomedical, oil-gas industry, aviation, marine, wearable electronics, fabrics, sensors, energy harvesting devices, and many more
A review on natural fibre-based composites. Part II: application of natural reinforcements in composite materials for automotive industry
No full textA review on natural fibre-based composites. Part I: structure, processing and properties of vegetable fibres
No full textStructure and properties of biodegradable wheat gluten bionanocomposites containing lignin nanoparticles
No full textDevelopment and characterization of bionanocomposites based on poly(3-hydroxybutyrate) and cellulose nanocrystals
Get PDFPoly(3-hydroxybutyrate) (PHB)-based bionanocomposites were prepared using various percentages of cellulose nanocrystals (CNCs) by a solution casting method. CNCs were prepared from microcrystalline cellulose using sulfuric acid hydrolysis. The influence of CNCs on PHB properties was evaluated using differential scanning calorimetry, Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetry and tensile testing. Vapor permeation and light transmission of the materials were also measured. Differential scanning calorimetric tests demonstrated that CNCs were effective PHB nucleation agents. Tensile strength and Young's modulus of PHB increased with increasing CNC concentration. Moreover, the PHB/CNC bionanocomposites exhibited reduced water vapor permeation compared to neat PHB and had better UV barrier properties than commodity polymers such as polypropylene. It was found that nanocomposites with 6wt% of CNCs had the optimum balance among thermal, mechanical and barrier properties.Fil: Seoane, Irene Teresita. 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: Fortunati, Elena. Università di Perugia; ItaliaFil: Puglia, Debora. Università di Perugia; ItaliaFil: Cyras, Viviana 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: Manfredi, Liliana Beatriz. 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
Methods for Improving the Integration of FunctionalizedCarbon Nanotubes in Polymers
No full textCarbon nanotubes (CNTs) are crystalline, tubular, carbon structures with extraordinary mechanical, chemical, optical, and electrical properties. These unique properties make CNTs potentially valuable in a wide range of end-use applications. We review various nanotube/polymer composite fabrication methods including physical mixing in solution, infiltration of monomers in the presence of a nanotube mat and chemical functionalization of CNTs by plasma treatment highlighting the current opportunities for efficiently translating the extraordinary properties of carbon nanotubes to polymer matrices in hopes of facilitating progress in this emerging area
Effect of cellulose nanocrystals and bacterial cellulose on disintegrability in composting conditions of plasticized PHB nanocomposites
Get PDFPoly(hydroxybutyrate) (PHB)-based films, reinforced with bacterial cellulose (BC) or cellulose nanocrystals (CNC) and plasticized using a molecular (tributyrin) or a polymeric plasticizer (poly(adipate diethylene)), were produced by solvent casting. Their morphological, thermal, wettability, and chemical properties were investigated. Furthermore, the effect of adding both plasticizers (20 wt % respect to the PHB content) and biobased selected nanofillers added at different contents (2 and 4 wt %) on disintegrability in composting conditions was studied. Results of contact angle measurements and calorimetric analysis validated the observed behavior during composting experiments, indicating how CNC aggregation, due to the hydrophilic nature of the filler, slows down the degradation rate but accelerates it in case of increasing content. In contrast, nanocomposites with BC presented an evolution in composting similar to neat PHB, possibly due to the lower hydrophilic character of this material. The addition of the two plasticizers contributed to a better dispersion of the nanoparticles by increasing the interaction between the cellulosic reinforcements and the matrix, whereas the increased crystallinity of the incubated samples in a second stage in composting provoked a reduction in the disintegration rate.Fil: Seoane, Irene Teresita. 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: Manfredi, Liliana Beatriz. 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: Cyras, Viviana 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: Torre, Luigi. Università di Perugia; ItaliaFil: Fortunati, Elena. Università di Perugia; ItaliaFil: Puglia, Debora. Università di Perugia; Itali
Historically Inspired Strategy to Achieve Sustainable and Effective Coloration of Bioplastics
No full textThe use of historical organic pigmentsis an interesting strategyto provide color nuances to biopolymers while achieving good solidoptical effects. In this work, aqueous extracts of logwood (LW) aretested as a natural source of color for the sustainable productionof an organic purple pigment (LWP) taking advantage of the historicallake approach. Different amounts of LWP (0.01-2% wt) are usedfor the effective coloration of polycaprolactone (PCL), polybutylenesuccinate (PBS), and polylactide (PLA). The full characterizationof LWP and LWP-treated biopolymer samples enables the spectral andcolor properties of the composites to be defined where the exceptionalcolor efficiency of LWP is demonstrated by the very low amount (0.5%wt) necessary to reach the saturation. The evolution of spectra andcolor coordinates under accelerated aging conditions is monitoredfor LWP-polymer samples. A 10-12% decrease of the visible absorptionband is detected after prolonged irradiation, resulting in a moderatecolor fading for PBS compared to PCL samples, while negligible changesare observed for PLA samples. The results demonstrate that LWP constitutesan efficient and sustainable source of color for the analyzed polymerswithout causing significant changes in the tensile and thermal propertiesof the polymeric matrix.Apurple pigment is prepared from a natural source followinga historical and sustainable procedure for the effective colorationof three different biopolymers
Effect of organically modified nanoclay on the miscibility, rheology, morphology and physical properties of diglycidyl ether of bisphenol-A epoxy/ carboxyl-terminated (butadiene-co-acrylonitrile) blend
No full textCarboxyl-terminated (butadiene-co-acrylonitrile) (CTBN) modified epoxy/clay nanocomposites (epoxy/clay/CTBN ternary nanocomposites) were synthesized using nadic methyl anhydride as curing agent. Effect of nanoclay on the phase behavior (UCST) of epoxy oligomer/CTBN blend has been studied in detail. The phase diagram was shifted to a higher temperature with increase in clay loading due to the easy penetration of low molecular weight CTBN into the clay galleries. The XRD studies confirmed the penetration of CTBN into the clay galleries, as the ‘ d ’ spacing increased with increase in CTBN content in the epoxy/clay/CTBN ternary nanocomposite. The interaction of organically modified clay with epoxy and CTBN were studied using frequency sweep rheological analysis. The individual and combined effect of nanoclay and CTBN on the cure reaction was followed by isothermal rheological analysis. It was found that complex viscosity profiles during cure reaction follow an exponential growth. The characteristic relaxation time of viscosity growth was described by the WLF equation. Moreover the dynamics of phase separation during cure was followed using optical microscopy. The scanning electron microscopic (SEM) images revealed that the domain size of phase separated CTBN in epoxy/clay/CTBN ternary nanocomposite was smaller than in epoxy/CTBN binary blend. The kinetic factor in epoxy-anhydride cure reaction and the presence of clay at epoxy–CTBN interface was used to explain this size reduction. The high resolution transmission electron microscopic (HRTEM) image of epoxy/3 phr clay nanocomposite showed that the clay platelets were mostly intercalated. Epoxy/3 phr clay/15 phr CTBN nanocomposite has an intercalated with occasional exfoliated microstructure with slightly distorted clay orientation. Low magnification TEM images showed that most of the clay platelets located near the phase separated CTBN and the presence of clay at the epoxy–CTBN interface. The viscoelastic properties of epoxy/clay/CTBN nanocomposite was studied and compared with that of epoxy/clay nanocomposite and epoxy/CTBN blend. A quantitative measurement of constrained region (macromolecular chains immobilized by the clay platelets) was carried out for epoxy/clay and epoxy/clay/CTBN nanocomposites. Finally thermal degradation studies were performed to evaluate the thermal stability of the ternary nanocomposites
Epoxy–carbon nanotube composites
No full textThe primary current objective is to develop knowledge-based technologies of carbon nanotubes, understanding the surface chemistry and processing tools used in designing polymer-based composites. The chapter emphasizes the different functionalization processes and the parameters affecting the nanotube dispersability in polymeric matrices. We also describe different processing methods for incorporating such functional nanofillers into the polymer backbone. How functionalized carbon nanotubes can improve the thermal, mechanical and electrical properties of common epoxy matrices already used in advanced applications is also reported. Moreover, the chapter reviews the different chemorheological approaches adopted to describe the catalytic effects of pristine and functionalized CNTs on the curing of epoxy systems through the development and application of coupled kinetic and rheological models. Finally, the effects of functionalized CNTs on the thermal, electric and mechanical properties are reviewed and explained in terms of the interactions between the functionalized CNTs and typical epoxy resins used in advanced applications
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