Home About us Contact
|
Home About us Contact | ||
|
|
||
Film Samples (film + sample)
Selected AbstractsThe Remarkable Thermal Stability of Amorphous In-Zn-O Transparent Conductors,ADVANCED FUNCTIONAL MATERIALS, Issue 20 2008Matthew P. Taylor Abstract Transparent conducting oxides (TCOs) are increasingly critical components in photovoltaic cells, low-e windows, flat panel displays, electrochromic devices, and flexible electronics. The conventional TCOs, such as Sn-doped In2O3, are crystalline single phase materials. Here, we report on In-Zn-O (IZO), a compositionally tunable amorphous TCO with some significantly improved properties. Compositionally graded thin film samples were deposited by co-sputtering from separate In2O3 and ZnO targets onto glass substrates at 100,°C. For the metals composition range of 55,84 cation% indium, the as-deposited IZO thin films are amorphous, smooth (RRMS,<,0.4,nm), conductive (,,,,3000,,,1,·,cm,1), and transparent in the visible (TVis,>,90%). Furthermore, the amorphous IZO thin films demonstrate remarkable functional and structural stability with respect to heating up to 600,°C in either air or argon. Hence, though not completely understood at present, these amorphous materials constitute a new class of fundamentally interesting and technologically important high performance transparent conductors. [source] Crystallization, orientation morphology, and mechanical properties of biaxially oriented starch/polyvinyl alcohol filmsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008Jing Wang Abstract Biaxially oriented starch/polyvinyl alcohol (PVA) films were prepared by stretching starch/PVA blend precursor films that were fabricated by extrusion casting via a twin-screw extruder. Investigations on crystallization, orientation morphology, and mechanical properties of extrusion cast and stretched starch/PVA films were carried out by using differential scanning calorimetry, scanning electron microscope, wide angle X-ray diffraction (WAXD), and tensile testing. The fresh extrusion-cast starch/PVA films, which were almost amorphous, can crystallize spontaneously when aged at room condition. A good compatibility between starch and PVA was obtained by extrusion-casting technology. The well-developed molecular orientation, which did not occur along the machine direction during the extruding process, was observed in stretched film samples. Stretching unaged films can induce crystallization and the orientation of crystalline structures during stretching, resulting in the changes in diffraction peaks of WAXD patterns. The effect of stretch ratio and the orientation distribution in the plane of the film on mechanical properties of stretched films was studied, and the equal biaxially oriented films were found to exhibit in-plane isotropy. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Strain rate mediated microstructure evolution for extruded poly(vinylidene fluoride) polymer films under uniaxial tensionJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2007F. Fang Abstract The deformation and fracture mechanism during uniaxial tension under controlled strain rates are investigated for extruded poly(vinylidene fluoride) (PVDF) polymer films at room temperature. It was found that both the longitudinal and transversal film-samples exhibited pronounced strain rate effect, that is, the yield stress increases while the fracture strain decreases with the increasing of strain rates. For the longitudinal film samples, phase transformation from the nonpolar ,-phase to the polar ,-phase occurs during the uniaxial tension, and the extent of the phase transformation enhances when the strain rate decreases. For the transversal film samples, no phase transformation was detected in all tested strain rates. By combining the stress,strain behavior and the X-ray results, it can be inferred that the conformational change from , to , phase during uniaxial tension contributes to the higher fracture strain of the longitudinal films than that of the transversal films. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1786,1790, 2007 [source] Synthesis and properties of methacrylate-based networked polymers having ionic liquid structuresJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 20 2010Kozo Matsumoto Abstract Methacrylate-based networked polymers having ionic liquid structures were prepared by radical copolymerization of methyl methacrylate (MMA) with multifunctional crosslinkers: ethyleneglycol dimethacrylate (EGDMA), trimethylolpropane trimethacrylate (TMPTMA), or triethyleneglycol dimethacrylate (TEGDMA), in the presence of 1-ethyl-3-methylethyl-1-imidazolium bis(trifluoromethane)sulfonyl imide (EMImTFSI). The fundamental physical properties of several film samples prepared by varying the monomer composition and ionic liquid content were investigated. The obtained materials became turbid with increasing crosslinker content and ionic liquid content. Their ionic conductivity increased with increasing ionic liquid content, while it was almost independent of the crosslinker content. EGDMA-derived materials and TMPTMA-derived materials showed higher ionic conductivity than TEGDMA-derived materials. TMPTMA-derived materials showed higher thermal stability than EGDMA or TEGDMA-derived materials. EGDMA and TMPTMA-derived materials were stiffer than the TEGDMA-derived materials. The elastic modulus of the film samples increased but the film became more brittle with the increase of crosslinker content. Scanning electron microscopy and atomic force microscopy observation revealed that phase separation of networked polymers and ionic liquid occurred in the highly crosslinked samples, and the phase separation structures became larger in scale with the increase of crosslinking density. This phase separation was considered to have a strong effect on the mechanical properties of the film samples. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 [source] Development of electronic nose method for evaluation of residual solvents in low-density polyethylene films ,PACKAGING TECHNOLOGY AND SCIENCE, Issue 2 2007Isinay E. Yüzay Abstract Flexible packaging films containing high levels of residual volatile organic compounds (VOCs) can alter the flavour and odour of packaged foods. Currently, a range of gas chromatographic techniques and sensory evaluations are used for assessing the residual VOCs in packaging films. An objective method for assessing the residual solvents from low-density polyethylene (LDPE) was developed using an Alpha MOS Fox 3000 electronic nose (e-nose) equipped with 12 metal oxide semiconductor sensors. Three VOCs, ethyl acetate, ethyl alcohol and toluene, were chosen as models for solvents of interest in flexible food packaging analysis. LDPE film samples were spiked with single and binary mixtures of solvents and analysed using the e-nose and by GC,FID (HP 6890; Hewlett-Packard Co., Wilmington, DE). The responses obtained from the e-nose were processed using principal component analysis (PCA) and discriminate factorial analysis (DFA) in order to identify the residual solvents. Partial least squares analysis (PLS) was also used to quantify the amount of residual solvent and to correlate the e-nose results with gas chromatography, which is currently the standard method for determining residual VOCs in packaging films. There was good agreement between the e-nose responses and gas chromatography results for single solvents (r = 0.90,0.98). The technique also worked for binary solvent mixtures (r = 0.84,0.99). The electronic nose can be a viable alternative to traditional techniques while providing simplicity and objectivity, which would be extremely advantageous in routine quality control of residual solvents. Copyright © 2006 John Wiley & Sons, Ltd. [source] Application of a computer model to evaluate the ability of plastics to act as functional barriersPACKAGING TECHNOLOGY AND SCIENCE, Issue 3 2003Jong-Koo Han Abstract A simulation model computer program, which accounts for not only the diffusion process inside the polymer but also partitioning of the contaminant between the polymer and the contacting phase, was developed based on a numerical treatment, the finite element method, to quantify migration through multilayer structures. The accuracy of the model in predicting migration was demonstrated successfully by comparing simulated results to experimental data. For this study, three-layer co-extruded high density polyethylene (HDPE) film samples, having a symmetrical structure with a contaminated core layer and virgin outer layers as the functional barriers, were fabricated with varying thickness of the outer layers and with a known amount of selected contaminant simulant, 3,5-di-t-butyl-4-hydroxytoluene (BHT), in the core layer. Migration of the contaminant simulant from the core layer to the liquid food simulants was determined experimentally as a function of the thickness of the outer layer at different temperatures. The computer program, developed as a total solution package for migration problems, can be applied not only to multilayer structures made with the same type of plastics but also to structures with different plastics, e.g. PP/PE/PP. This work might provide the potential for wider use of recycled plastic, especially polyolefins, which have lower barrier properties, in food packaging, and simplification of the task of convincing the FDA that adequate safety guarantees have been provided. Copyright © 2003 John Wiley & Sons, Ltd. [source] Effect of photo-initiators on melt degradation of polypropylene and starch-filled polymer,POLYMER INTERNATIONAL, Issue 10 2002Rouhallah Bagheri Abstract Six series of the processed polypropylene (pp) samples containing 0.25,1,wt% photo-initiators (PIs, four aromatic carbonyl, two ferric compounds) and also a series of 6,wt% corn-starch-filled pp containing 0.5,wt% of each PI, were prepared using a mixer in a closed system at 180,°C for 5,min. The melt flow index (MFI) and apparent viscosity measurments of the processed pp,PI samples showed a large increase in MFI/or decrease in apparent viscosity at 0.25,wt% of the PIs. Further increase in the amounts of PIs led these properties to reach a constant value at 0.5,wt% of the PIs. The presence of corn starch in the samples corresponded to a much lower increase in the MFI or decrease in the apparent viscosity. Ferric stearate and Irgacure 184 amoung the PIs showed the highest and lowest melt degradation effects, respectively. Carbonyl measurments of all the film samples showed good correlations between chemical changes in the pp structure and variations in the flow properties during processing. UV absorption of the films also evidenced the presence of the aromatic carbonyl PIs in the pp matrix after melt processing. © 2002 Society of Chemical Industry [source] Production and Characterization of Poly-,-hydroxyalkanoate Copolymers from Burkholderiacepacia Utilizing Xylose and Levulinic AcidBIOTECHNOLOGY PROGRESS, Issue 6 2004Thomas M. Keenan Poly(,-hydroxybutyrate - co -,-hydroxyvalerate) (P(3HB - co -3HV)) copolymers were prepared via shake-flask fermentations of Burkholderia cepacia(formerly Pseudomonas cepacia) containing 2.2% (w/v) xylose and concentrations of levulinic acid ranging from 0.07% to 0.67% (w/v). Periodic harvest of shake-flask cultures from 48 to 92 h post-inoculation yielded 4.4,5.3 g/L of dry cell biomass, containing 42,56% (w/w) P(3HB - co -3HV), with optimal product yield occurring between 66 and 74 h. Growth and PHA accumulation enhancement were observed with concentrations of levulinic acid from 0.07 to 0.52% (w/v), producing dry cell biomass and P(3HB - co -3HV) yields of 9.5 and 4.2 g/L, respectively, at the 0.52% (w/v) concentration of levulinic acid. Representative samples were subjected to compositional analysis by 300 MHz 1H and 150 MHz 13C NMR, indicating that these random copolymers contained between 0.8 and 61 mol % 3-hydroxyvalerate (3HV). Solvent-cast film samples were characterized by differential scanning calorimetry, which demonstrated melting temperatures ( Tm) to decrease in a pseudoeutectic fashion from 174.3 °C (0.8 mol % 3HV) to a minimum of 154.2 °C (25 mol % 3HV) and the glass transition temperatures ( Tg) to decrease linearly from 2.1 to ,11.9 °C as a function of increasing mol % 3HV. Thermogravimetric analysis of the copolymer series showed the temperature for onset of thermal decomposition ( Tdecomp) to vary as a function of mol % 3HV from 273.4 to 225.5 °C. Intrinsic viscosities (,) varied from 3.2 to 5.4 dL/g, as determined by dilute solution viscometry. Viscosity average molecular weights ( Mv) of the copolymers were determined to range from 469 to 919 kDa, indicating that these P(3HB - co -3HV) copolymers are of sufficient molecular mass for commercial application. [source] | ||||||||||