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Good Adhesion (good + adhesion)
Selected AbstractsNovel repair method for technical enamels based on sol,gel and sol-dispersion coatings,MATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 2 2008S. Benfer The aim of the work presented here is the development of a novel repair method for technical enamels by using chemical nanotechnology. Good adhesion of coatings requires good wettability of the substrate by the repair solution. This was achieved by different pre-treatments of the steel substrates. Low sintering temperatures of the coatings can be ensured by the use of nanoparticle-based systems. Based on liquid metal alkoxides, a colloidal alumina sol and metal salts homogeneous sols with up to seven enamel compounds were prepared. The sols were brush coated onto plain and partly enamelled steel substrates and sintered in a furnace, by inductive heating or an IR emitter. Thin (single layer,,,1µm) crack-free layers were obtained on nearly all substrates independent of the sintering conditions investigated. The local sintering methods (IR emitter, inductive heating) allow to produce multiple coating systems in short times. Electrochemical impedance spectroscopy (EIS) provides evidence of the protective effect of these layers compared to the bare substrate, but as a result of their chemical composition the layers are not stable in the electrolytic environment for longer times. The thickness of such multiple coatings (20 layers, ,,8 µm) is still small compared to that of a technical enamel. Therefore, sol dispersion systems containing powder particles and sol components are applied on top of the sol,gel layers to increase the thickness of the sintered layers. [source] Synthesis of organic,inorganic hybrid polymeric nanocomposites for the hard coat applicationJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2007Chuan Hsiao Shu Abstract An organic,inorganic hybrid polymeric nanocomposite has been synthesized for making UV-curable hard coats. This nanocomposite consists of nano-sized colloidal silica functionalized with vinyltriethoxysilane (VTES) and dendritic acrylic oligomers (DAO) which have been formed earlier via a reaction of ethylenediamine (EDA) with trimethylopropane triacrylate (TMPTA). Applied as a hard coat on top of a polyethylene terephthalate (PET) film, this nanocomposite has a short UV-cure time and the cured coat has an enhanced thermal decomposition temperature (Td), 89,90% transparency, increased hardness up to 3H, better adhesion up to 4B, and a flat surface with a root mean square roughness of 2,4 nm. The preparation as well as the characterization of the constituting species and the final hybrid are described in detail. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3985,3993, 2007 [source] Preparation of Cross-Linked Poly[(, -caprolactone)- co -lactide] and Biocompatibility Studies for Tissue Engineering MaterialsMACROMOLECULAR BIOSCIENCE, Issue 1 2007Hiroshi Miyasako Abstract In this study, cross-linked materials were prepared using the branched macromonomer with different CL/LA molar ratios, and feasibility studies for tissue engineering were carried out. The thermal and mechanical properties of these materials depended on the CL/LA compositions; however, there was no change in the wettability of each material. The HeLa cells adhesion and growth on the CL-LA7030c were equal to that on the commercially available polystyrene dish. The protein absorption experiment using the FBS proteins revealed that the materials with well-grown cells showed better adhesion of the proteins. [source] Improved patient acceptability with a transdermal drug-in-adhesive oestradiol patchAUSTRALIAN AND NEW ZEALAND JOURNAL OF OBSTETRICS AND GYNAECOLOGY, Issue 3 2000Yvonne Lake SUMMARY The aim of this trial was to assess the relative patient acceptability of two transdermal oestradiol patches used in treatment of oestrogen deficiency in postmenopausal women. Thirty-five hysterectomised postmenopausal women with no previous experience of transdermal oestradiol delivery systems received treatment with either once-weekly drug-in-adhesive (DIA) patches or twice-weekly reservoir patches for 4 weeks, and were then switched to the alternative treatment for a further 4 weeks. At the end of the study, the patients completed a questionnaire to assess their relative preference for a number of characteristics of the 2 transdermal systems and, where possible, their preference for transdermal compared with oral hormone replacement therapy. Thirty-one patients completed the study; four withdrew during treatment with the reservoir patch. The DIA patch was preferred for being ,easiest to remember to apply' by 80% of patients (p < 0.01), ,easiest to open' and ,easiest to apply' by 68% (p = 0.025), and as having ,best cosmetic appearance' by 65% (p = 0.05) and ,best overall skin adhesion' by 61% (p < 0.01). While 10% of patients rated the reservoir patch as ,least irritating to the skin' (p = 0.03), only one patient found this patch ,most comfortable to wear' (p < 0.01). The DIA patch was selected by 87% of patients as their preferred treatment overall (p = 0.001). Ninety-one per cent of 22 responding patients were at least as confident of treatment with transdermal patches as with oral hormone replacement therapy (p = 0.006) and 74% of 27 responders preferred transdermal to oral treatment (p = 0.004). The DIA patch appears to be more acceptable to patients than the reservoir patch as a transdermal oestradiol delivery system for the treatment of postmenopausal oestrogen deficiency. Characteristics of the DIA patch which may account for improved patient acceptance include ease of remembering once-weekly patch application, improved cosmetic appearance and comfort, and better adhesion. [source] Chemical, Mechanical, and Antibacterial Properties of Silver Nanocluster,Silica Composite Coatings Obtained by Sputtering,ADVANCED ENGINEERING MATERIALS, Issue 7 2010Monica Ferraris Abstract Silver nanocluster,silica matrix composite coatings have been deposited by radio frequency (RF) co-sputtering on silica substrates. Field emission scanning electron microscopy and X-ray diffraction spectra of the as deposited and heated samples (150,600,°C) revealed the presence of metal silver nanoclusters, their size depending on the heating treatment. The antibacterial activity of the as deposited and heated samples has been measured in accordance to National Committee for Clinical Laboratory Standards, and it has been demonstrated on samples heated up to 450,°C in contact mode and for samples heated at 600,°C in a liquid environment. Their antibacterial activity was still present after gamma ray and ethylene oxide gas (EtO) sterilization of the samples. Silver leaching tests on the as deposited and heated samples has been measured by graphite furnace atomic absorption spectrometer, revealing an amount ranging from 0.1 to 0.9,µg mm,2, over 28 days. Tape resistance (ASTM D3359-97) and scratch resistance tests have been done on each sample revealing a good adhesion of the coatings on silica. [source] Diamond Transistor Array for Extracellular Recording From Electrogenic CellsADVANCED FUNCTIONAL MATERIALS, Issue 18 2009Markus Dankerl Abstract The transduction of electric signals from cells to electronic devices is mandatory for medical applications such as neuroprostheses and fundamental research on communication in neuronal networks. Here, the use of diamond with its advantages for biological applications as a new material for biohybrid devices for the detection of cell signals is investigated. Using the surface conductivity of hydrogen-terminated single-crystalline diamond substrates, arrays of solution-gate field-effect transistors were fabricated. The characterization of the transistors reveals a good stability in electrolyte solutions for at least 7 days. On these devices, cardiomyocyte-like HL-1 cells as well as human embryonic kidney cells (HEK293), which were stably transfected with potassium channels, are cultured. Both types of cells show healthy growth and good adhesion to the substrate. The diamond transistors are used to detect electrical signals from both types of cells by recording the extracellular potential. For the HL-1 cells, the shape of action potentials can be resolved and the propagation of the signal across the cell layer is visible. Potassium currents of HEK293 cells are activated with the patch-clamp technique in voltage-clamp mode and simultaneously measured with the field-effect transistors. The ion sensitivity of the diamond surface enables the detection of released potassium ions accumulated in the cleft between transistor and cell. [source] Melt mixing of carbon fibers and carbon nanotubes incorporated polyurethanesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008Shahrul Azam Abdullah Abstract Polyurethane composites filled with carbon fibers (CF) and carbon nanotubes (CNT) were prepared by mixing and injection molding, and its mechanical as well as their thermal properties were investigated. Dynamic mechanical analysis (DMA), thermogravimetry analysis (TGA), and thermal conductivity tests were done, and the properties were evaluated as a function of the filler concentration. The storage modulus of the composites increased with fillers concentration, which also mean the increase of the stiffness, suggest a good adhesion between the polyurethane matrix and the fillers. Addition of more CF and CNT to the composites broadened and lowered the peak of tan , specifies that the polyurethane composite became more elastic because there is a good adhesion between the fillers and the matrix. The addition of carbon fillers improves the thermal stability of the polyurethane. The inclusions of CNT show a better thermal stability when compared with CF. The addition of carbon fillers also increased the thermal conductivity of the polyurethane composites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Polyethersulfone-epoxy terminated materials as thermosetting resins for microelectronic devicesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 21 2009Emilio Scamporrino Abstract A totally aromatic polyether/sulfone resin (PES-E) was synthesized and tested as an insulating glue in the construction of a Chip-on-Chip (CoC) device. PES-E, essentially constituted of open-chain macromolecules of low molecular mass (Mn of about 3000 Da) with hydroxy and/or epoxy end-groups, has a glass transition temperature of about 150 °C and is subject to crosslinking at temperatures higher than 320 °C. A CoC device was assembled using a five-step process by interposing a layer of PES-E between two chips. After curing, SEM cross section images showed a homogeneous crosslinked resin layer well stuck (flick and shear tests) to both chips. The chemical structure of the chains and the hydroxy/epoxy end-groups ratio were optimized to obtain a crosslinked material with good adhesion and sufficient flexibility to avoid cracking during assembly and use. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5682,5689, 2009 [source] Fabrication of Gas Electrodes by Wet Powder Spraying of Binder-Free Particle Suspensions Using a Pulse Injection ProcessJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 5 2007Naoki Oishi A process for wet powder spraying of binder-free particle suspensions using pulse injection was devised for the fabrication of gas electrodes. The resulting deposited electrodes were found to have fine and uniformly distributed pores, to have good adhesion, and low interfacial resistance on electrolyte substrates. The uniformity of the layers was improved by decreasing the spray pulse to 0.05 s with a 1-s off period. Even without drying or any pre-treatments before firing, there was no cracking or delamination of the deposited layer. The deposited layer remained porous, crack-free, and well bound to the substrate after firing. [source] Disulfide-Crosslinked Electrospun Poly(, -glutamic acid) Nonwovens as Reduction-Responsive ScaffoldsMACROMOLECULAR BIOSCIENCE, Issue 6 2009Hiroaki Yoshida Abstract Novel water-insoluble, and reduction-responsive nonwoven scaffolds were fabricated from , -PGA and tested in cell culture. An electrospinning method was developed to produce scaffolds of fibers with diameters of 0.05,0.5 µm. Crosslinking of the fibers with cystamine in the presence of EDC resulted in water-insoluble , -PGA nonwovens with disulfide crosslinkages. These crosslinked fibers were easily decomposed under physiological conditions using L -cysteine, a biocompatible reductant. In vitro experiments with mouse L929 fibroblasts showed good adhesion onto , -PGA-SS fiber matrices and excellent cell proliferation. These , -PGA-SS nonwovens can be used as novel biocompatible and biodegradable scaffolds with reduction-responsiveness for biomedical or tissue engineering applications. [source] Boron nitride phosphide thin films grown on quartz substrate by hot-filament and plasma-assisted chemical vapor depositionPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 13 2004X. W. Zhang Abstract Boron nitride phosphide films are, for the first time, grown on transparent quartz substrate by hot filament and radio-frequency plasma co-assisted chemical vapor deposition technique. XPS, XRD, SEM, and UV measurements are performed to study the chemical composition, crystallization, microstructure, and optical absorption, respectively. A "centipede-like" microstructure and undulating ground morphology on the film surface are observed, and their growth mechanism is speculated upon. The chemical composition is determined as BN1,xPx, whose characteristic XRD peak is preliminarily identified. The optical band gap can be modulated between 5.52 eV and 3.74 eV, simply by adjusting the phosphorus content in BN1,xPx through modifying the PH3 flux during the film-deposition process. The merits of the BN1,xPx film, such as high ultraviolet photoelectric sensitivity with negligible sensitivity in the visible region, modifiable wide optical band gap, and good adhesion on transparent substrate, suggest potential applications for ultraviolet photo-electronics. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Adhesion control for injection overmolding of polypropylene with elastomeric ethylene copolymersPOLYMER ENGINEERING & SCIENCE, Issue 10 2009Marco Dondero Two types of random semicrystalline copolymers (ethylene,octene and ethylene,butene) were overmolded on a core polypropylene. Maximum solid,liquid interface temperature achieved for the overmolding injection process is used as the key parameter for adhesion control. The main bonding process is shown to be a Rouse-type fingering mechanism that develops in short time scales. Normalized peel tests were conducted on overmolded samples to measure the resulting polypropylene copolymers' bonding strength. All the ethylene random copolymers used for this study give good adhesion to polypropylene in overmolding processes, provided the right range of interface temperature is reached. Adhesion strength can be easily controlled for efficient debonding and recycling of used overmolded parts. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers [source] Role of polymer chain end groups in plasma modification for surface metallization of polymeric materialsPOLYMER INTERNATIONAL, Issue 6 2009Norihiro Inagaki Abstract How to improve adhesion between poly(oxybenzoate- co -oxynaphthoate) (Vecstar OC and FA films) and copper metal by Ar, O2, N2 and NH3 plasma modification was investigated. The mechanism of adhesion improvement is discussed from the viewpoint of chemical and physical interactions at the interface between the Vecstar film and copper metal layer. The adhesion between Vecstar OC film and copper metal was improved by chemical rather than physical interactions. Polymer chain end groups that occur at Vecstar OC film surfaces contribute effectively to adhesion. This improvement in adhesion is due to interactions between copper metal and OC groups formed by plasma modification. Aggregation of the OC groups to the copper metal/Vecstar OC film interface is a key factor for good adhesion. From this aspect, heat treatment of plasma-modified Vecstar OC films on glass plates is effective in the aggregation, and the peel strength for the copper metal/Vecstar OC film system reached 1.21 N (5 mm),1. Copyright © 2009 Society of Chemical Industry [source] Towards advanced circuit board materials: adhesion of copper foil to ultra-high molecular weight polyethylene compositePOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 6 2002Dmitry Abstract Polyethylene based composites are attractive materials for advanced circuit board applications because of their unique combination of properties: low dielectric constant and loss factor, light weight, high flexural modulus and low thermal expansion coefficient controlled in all spatial directions. This investigation describes a process to consolidate chopped fibers of ultra-high molecular weight polyethylene concurrently with its bonding to a copper foil. Bonding is affected by a thin sheet of low-density polyethylene, incorporating a crosslinking agent with a concentration gradient across the sheets thickness. In this single step process, the composite material is formed and bonded to the metal foil, achieving good adhesion without the use of extraneous glue. Copyright © 2002 John Wiley & Sons, Ltd. [source] Valorization of an industrial organosolv,sugarcane bagasse lignin: Characterization and use as a matrix in biobased composites reinforced with sisal fibersBIOTECHNOLOGY & BIOENGINEERING, Issue 4 2010Elaine C. Ramires Abstract In the present study, the main focus was the characterization and application of the by-product lignin isolated through an industrial organosolv acid hydrolysis process from sugarcane bagasse, aiming at the production of bioethanol. The sugarcane lignin was characterized and used to prepare phenolic-type resins. The analysis confirmed that the industrial sugarcane lignin is of HGS type, with a high proportion of the less substituted aromatic ring p -hydroxyphenyl units, which favors further reaction with formaldehyde. The lignin,formaldehyde resins were used to produce biobased composites reinforced with different proportions of randomly distributed sisal fibers. The presence of lignin moieties in both the fiber and matrix increases their mutual affinity, as confirmed by SEM images, which showed good adhesion at the biocomposite fiber/matrix interface. This in turn allowed good load transference from the matrix to the fiber, leading to biobased composites with good impact strength (near 500,J,m,1 for a 40,wt% sisal fiber-reinforced composite). The study demonstrates that sugarcane bagasse lignin obtained from a bioethanol plant can be used without excessive purification in the preparation of lignocellulosic fiber-reinforced biobased composites displaying high mechanical properties. Biotechnol. Bioeng. 2010;107:612,621. © 2010 Wiley Periodicals, Inc. [source] | ||||||||||||||||||||||