Papers by Keyword: Hybrid Material

Abstract: Hybrid materials offer great potential for weight and cost reduction, function integration and improved mechanical properties. A whole range of parts or application areas are conceivable (especially in the field of lightweight design). In terms of implementation, it is possible to produce fully or partially joined semi-finished parts from metallic, organic or inorganic materials. Semi-finished parts of this type can be used in applications ranging from simple reinforcements to complex hollow structures in automobiles. Innovative production processes are necessary for the efficient manufacture of these parts. This is why the current research and development work is focused on making complex, hollow work pieces from hybrid semi-finished materials and on manufacturing methods for the partially joined semi-finished parts. A new and innovative incremental joining process with inline electrochemical treatment is opening up interesting perspectives here. For the manufacture of complex work pieces, the use of adapted sheet-metal-forming processes, like deep drawing or working-media-based high pressure forming, is highly promising and will be addressed in the paper.

Abstract: Organic-inorganic hybrid materials doped with Eu3+, Tb3+ La3+ and lithium ions were produced by sol-gel method using Tetraethyl orthosilicate and poly(methyl methacrylate), ethyl methacrylate, butyl methacrylate, ethyl acetyloacetate as inorganic and organic precursors. Morphology and structure of the hybrids heated at 125°C were characterized by Scanning electron microscopy equipped with Energy dispersive X-ray spectroscopy (SEM/EDS, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), 29Si MAS Nuclear Magnetic Resonance. In all the hybrids, photoluminescence emissions from (5D3), 5D4 →7FJ and 5D0→7FJ transi^{Superscript text}tions of Eu3+ and Tb3+ ions were revealed.

Abstract: Single crystalline Y(OH)3 nanorods were synthesized from Y2O3 powder by a simple hydrothermal synthesis method under alkaline conditions. SEM images displayed that the nanorods have average diameters of about 400nm and lengths up to several micrometers. In this paper, it is used nano-inorganic particles yttrium hydroxide to modified MC nylon. The different mass fraction of yttrium hydroxide has affected mechanical and thermal properties of the MC nylon composites. The results show that with increasing of the mass fraction of yttrium hydroxide, the impact strength is the highest value when yttrium hydroxide mass fraction of 0.25wt%, however the tensile strength decrease 20%. And there is a little change in thermal stability when Yttrium Hydroxide added.

Abstract: Organic/inorganic hybrid materials based upon stimuli-responsive copolymers have attracted an inceasing attention. Compared with the polymeric materials, these hybrid materials can form aggregates in aqueous solution with much more stable shape-persistance due to the inorganic structure, which facilitate the mass delivery and long-term life. A novel hybrid material based on a new reactive block copolymer, poly(ethylene oxide)-block-poly{3-(trimethoxysilyl)propyl methacrylate-co-N-isopropylacrylamide-co-6-[4-(4-methoxyphenylazo)phenoxy]hexyl methacrylate} [PEO-P(TMSPMA-NIPAM-AzoMA)] was synthesized via atom transfer radical polymerization (ATRP). The vesicles were obtained by self-assembly of the resulting block copolymer in a selective solvent, and then the PTMSPMA block was subjected to hydrolysis and polycondensation reaction to fix vesicle wall in the presence of triethylamine as a catalyst. The photo- and thermo- dual-responsive properties of the vesicles were investigated.

Abstract: In this study, liquid crystalline copper phthalocyanine and single walled carbon nanotubes were dispersed in solution to prepare novel composites. Thin films of these composites prepared by solving of the composite in dimetylformamide and then by spin coating the solution onto the substrates were studied by the methods of polarizing microscopy, polarized Raman and optical absorption spectroscopies. It was shown that pure CuPcR₄ forms the films with a herringbone arrangement of phthalocyanine molecules within adjacent columns. An addition of carbon nanotubes (0.5-2 wt %) to CuPcR₄ leads to formation of the films with edge-on orientation of the molecules. The higher conductivity values were found for the films of phthalocyanine containing SWCNT. The lateral conductivity tends to decrease with the increase of SWCNT concentration from 0.5 to 2 wt %.

Abstract: The new hybrid material, (C₄H₁₂N₂)[Co(H₂O)₄(SeO₄)₂]·2H₂O, has been synthesized by the slow evaporation method at room temperature and crystallographically characterized. It crystallizes in the monoclinic system, space group P21 /n. The crystal structure of this compound consists of transition metal, Co(II), octahedrally coordinated by four water molecules and two selenate groups forming the [Co(H₂O)₄(SeO₄)₂]^2- anions, water molecules and piperazinediium cations (C₄H₁₂N₂)²⁺ linked together by two types of hydrogen bonds, OW–H…O and N–H…O.

Abstract: Minimum-weight designs are frequently too costly to manufacture, whereas less expensive and easy to fabricate and assemble designs are often much heavier. The most efficient design on the basis of both cost and weight often lies between these two extremes. The current trend in structural materials selection consists of the extensive use of composite materials in the airframe. Composite materials have high specific strength, are less prone to fatigue crack initiation and provide enhanced flexibility for structural optimization compared to the aluminum alloys. On the other hand, aluminum alloys display higher toughness and better damage tolerance in the presence of defects. A simple methodology for the weight assessment based on the specific weight for different damage scenarios for an exemplary, simplified fuselage panel, will be presented, in order to quantify the savings under different conditions. The results show that the composites have advantages over the aluminum alloys, although due to low ductility, in parts that are exposed to external damages the aluminum alloys can have better performance due to the better damage tolerant properties.

Abstract: UV resistance of hybrid nanocomposite films of γ-Glycidoxypropyltrimethoxysilane (GPTMS)/TiO₂-ZrO₂ prepared by Tetrabutoxytitanate, Zirconium n-tetrabutanoxide and GPTMS via sol-gel method were analyzed by observation of the film appearance, thermal gravimetric analysis (TGA), UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR) before and after UV irradiation. It was found that cracks on the hybrid films increase with irradiation time, total inorganic content and the content of TiO₂. The transmittance of the hybrid film increased with the increase of ZrO₂ content, which blocks part of the photo catalysis effect of TiO₂. When the ZrO₂ content increased to equal with TiO2, UV resistance of the hybrid film approaches that of pure ZrO2. The irregular behavior of yellow index data indicates that the deterioration in transmittance is caused by cracks mainly. FTIR results show that the hybrid film of TiO₂/ZrO₂(3/1) (T₃Z) still retains a stronger photo catalysis effect, after UV irradiation, the peak indicating the concentration of –OH enlarged greatly, while that of the pure ZrO₂ hybrid film remains unchanged.

Abstract: Octaepoxysilsesquioxane (POSS-Ep), a kind of functional polyhedral oligomeric silsesquioxane (POSS) was cured with 4,4'-diaminodiphenylsulfone diamine (DDS) in this study. Possessing epoxy groups, it can be cured thermally with certain curing agents including amines. Differential scanning calorimetry (DSC) was used to determine the curing techniques of the POSS-Ep/DDS resin system in this study. The appropriate curing technique for this resin is set as: 130°C/2h+ 160°C/2h+200°C/2h.

Abstract: Cyanate ester resin (CE)/epoxy functionalized polyhedral oligomeric silsesquioxane (POSS-Ep) organic-inorganic hybrids were prepared by casting and curing. The hybrid resin systems were studied by gel time test to evaluate the effect of POSS-Ep on curing reactivity of CE. Impact and flexural strengths of the hybrids were investigated. The thermal properties of the hybrids were studied by thermogravimetric analysis (TGA). TGA results show that CE10 also possesses the best thermal stability. The initial temperature of decomposition (Ti) of CE10 is 426 oC, 44 oC higher than that of the pristine CE.