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Different Films (different + film)
Selected AbstractsElectrical properties of modified-grafted polypropyleneJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2007Naeem M. El-Sawy Abstract The electrical properties of polypropylene (PP), grafted polypropylene (PP- g -PVP), and modified-grafted PVP with ,-cyano-,-(2-thienyl) crotononitrile were investigated. Also, the electrical characteristic of the modified-grafted PVP subjected to ,-irradiation (60 kGy) was studied. The results show that the , of trunk polymer undergoing different degree of grafting generally increases as function of the grafting yield. The grafting yield between 64.1 and 149% resulted in a progressive decrease in ,E, value. Inclusion of sulfur-containing substrate in different films, having various grafting yields, leads to both increase and decrease in , values. A significant increase in , values is observed upon inclusion of sulfur-containing substrate having maximum grafting yield (149%). These changes are accompanied by fluctuation in , values. The exposure of sulfur-containing substrate in grafting film to a dose of 60 kGy results in a significant decrease in ,E, values for the films undergoing a grafting yield between 64.1 and 149%. The observed changes in ,E, of different films investigated could be attributed mainly to corresponding changes in , values. The observed improvement in electrical properties is mainly because of possible increase in concentration of charge carrier and/or their mobilities. The scanning electron micrographs of some selected films show significant changes in the morphology of the films investigated due to changing the grafting yield, inclusion of sulfur-containing substrate, and exposure to ,-irradiation. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3797,3803, 2007 [source] OXYGEN TRANSMISSION RATE THROUGH MICRO-PERFORATED FILMS: MEASUREMENT AND MODEL COMPARISONJOURNAL OF FOOD PROCESS ENGINEERING, Issue 2 2001V. GHOSH ABSTRACT Static and flow-through techniques were used to experimentally measure the oxygen transmission rate of micro-perforated films. The static method simulates the actual package conditions but is very time consuming. Whereas, the flow-through method is relatively simple and takes less time to give the results, but it gave higher values than that obtained by the static method. A regression equation was developed to correlate the data obtained by these two methods. Published models for predicting gas exchange through micro-perforations were evaluated. The predicted data by these models were compared with the experimental data obtained by the static method and the flow-through method for six different films. The model proposed by Fishman et al. (1996) (J=-D(c-cA)/Lh; Lh= thickness of the film + radius of the perforation) had very good agreement with the experimental data from the static method. [source] Evaluation of different varieties of cauliflower for minimal processingJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 2 2007Susana Sanz Abstract The impact of minimal processing technology on the sensory quality and the growth of micro-organisms in eight varieties of cauliflower packaged in four different films (one PVC and three P-Plus) was measured and quantified during more than 25 days of storage at 4 °C. Other important parameters such as weight loss and gas concentration in the packages were also determined. The composition of the atmosphere in the packages of minimally processed cauliflower depended on both the permeability of the film used for the packaging and the variety of cauliflower. When establishing shelf-life, loss of sensory quality was the deciding factor rather than loss of microbiological quality. The initial microbial load proved more important than the composition of the atmosphere inside the packages. In sensory evaluation the most important aspect was colour. In instrumental evaluation, coordinate b* was the main means of estimating shelf-life. The combination of P-Plus 120 film and varieties of cauliflower of large size and great vigour allowed the atmosphere inside the packages to have an O2 level below 10% and a CO2 level above 10%. That atmosphere composition proved essential for maintaining the sensory quality of minimally processed cauliflower. In these conditions, samples attained a shelf-life of more than 25 days. However, the different behaviours of the cauliflower varieties make it necessary to establish particular packaging conditions. The use of less permeable films than those used in this study, or the use of actively modified atmospheres, could be an alternative for those varieties that require special packaging conditions when processed using this technology. Copyright © 2006 Society of Chemical Industry [source] Interaction of Plasma Deposited HMDSO-Based Coatings with Fibrinogen and Human Blood Plasma: The Correlation between Bulk Plasma, Surface Characteristics and Biomolecule InteractionPLASMA PROCESSES AND POLYMERS, Issue 5 2010Ram P. Gandhiraman Abstract The success of a biomaterial depends on the nature of interaction and the progressive reaction between the biological components and the surface of the biomaterial. In order to control the interaction between the biomaterial and biological component, it is necessary to understand the factors that influence the protein adsorption and cell proliferation. Surface chemistry plays a crucial role in the success of any blood contacting biomaterial. Plasma enhanced chemical vapour deposition (PECVD) is an interesting commonly used technique for tailoring surface characteristics while retaining bulk material properties. Two different films, namely polymer-like and silica-like coatings, with varying surface characteristics have been deposited from hexamethyldisiloxane, by PECVD, on 316L stainless steel. A correlation between the bulk plasma, interfacial adhesion of the coating to 316L steel, surface characteristics and biomolecule interaction is presented in this work. The interfacial adhesion strength analysis demonstrated that silica-like coatings have higher adhesion strength to 316L stainless steel than polymer-like coatings, caused due to the formation of a strong FeOSi and CrOSi bonds. It was observed that the effect of nanoscale surface roughness (close to 6,nm) was less significant, and that the surface chemistry played a significant role in governing the fibrinogen adsorption. Highest fibrinogen adsorption on plain steel was due to the electrostatic interaction of the metal oxide layer with the protein. Hydrophobicity of the polymer-like film resulted in a higher fibrinogen binding than the silica-like films. [source] In Situ Spectroscopic Characterization of Rectifying Molecular Monolayers Self-Assembled on GoldCHEMPHYSCHEM, Issue 15 2007Alberto Girlando Prof. Abstract We report visible, Raman, and infrared spectra of self-assembled monolayers (SAMs) formed by the donor-(,-bridge)-acceptor chromophore, Z -,-[N -(,-acetylthioalkyl)-4-quinolinium]-,-cyano-4-styryldicyanomethanide (CH3CO-S-CnH2n -Q3CNQ where n=8, 10), on gold-coated substrates. The data are compared with the spectra collected for the same compound in solution and in the solid state, and with those obtained for a Langmuir,Blodgett (LB) monolayer of C16H33 -Q3CNQ deposited on gold. Spectral analysis confirms that in solution, in the solid state and in the LB film the chromophore has a zwitterionic (D+ -,-A,) ground state. At variance with this well-known result, our data show that in SAMs deposited on gold the chromophore has a more neutral, quinoid ground state. We relate this difference to the different packing of the molecules in the two different films: in SAMs in fact the chromophores stand almost vertical with respect to the substrate, whereas in LB films they make an angle of about 45 degrees. The Q3CNQ molecule is a well-known molecular rectifier, and for SAMs we were able to check the direction of electron flow at forward bias on the same samples that have been characterized spectroscopically, shedding light on the rectification mechanism. [source] | |||||||||||||