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Peel Test (peel + test)
Selected AbstractsTowards the algorithmic treatment of 3D strong discontinuitiesINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 2 2007J. Mergheim Abstract A geometrically non-linear finite element framework for the modelling of propagating discontinuities in three-dimensional continua is presented. By doubling the degrees of freedom in the discontinuous elements, the algorithm allows for arbitrary discontinuities which are not restricted to inter-element boundaries. The deformation field is interpolated independently on both sides of the discontinuity. In contrast to the X-FEM, the suggested approach thus relies exclusively on displacement degrees of freedom. On the discontinuity surface, the jump in the deformation is related to the cohesive tractions to account for smooth crack opening. Computational difficulties characteristic of three-dimensional crack propagation are addressed. The performance of the method is elaborated by means of a homogeneous three-dimensional tension problem and by means of the classical peel test. Copyright © 2006 John Wiley & Sons, Ltd. [source] Click chemistry in materials synthesis.JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 22 2007Abstract 1,2,3-Triazole-based polymers generated from the Cu(I)-catalyzed cycloaddition between multivalent azides and acetylenes are effective adhesive materials for metal surfaces. The adhesive capacities of candidate mixtures of azide and alkyne components were measured by a modified peel test, using a customized adhesive tester. A particularly effective tetravalent alkyne and trivalent azide combination was identified, giving exceptional strength that matches or exceeds the best commercial formulations. The addition of Cu catalyst was found to be important for the synthesis of stronger adhesive polymers when cured at room temperature. Heating also accelerated curing rates, but the maximum adhesive strengths achieved at both room temperature and high temperature were the same, suggesting that crosslinking reaches the same advanced point in all cases. Polytriazoles also form adhesives to aluminum, but copper is bound more effectively, presumably because active Cu(I) ions may be leached from the surface to promote crosslinking and adhesion. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5182,5189, 2007 [source] Correlation of peel and burst tests for pouchesPACKAGING TECHNOLOGY AND SCIENCE, Issue 2 2001Rosamari Feliú-Báez Abstract Theoretical equations based on force diagrams were developed in order to explain pouch behaviour during a restrained burst test. According to the resulting equation, P,=,2 S/D, the burst pressure (P) increases directly with seal strength (S) and inversely with the distance between the restraining plates (D). After performing a restrained burst test and a peel test on Tyvek/plastic pouches, it was found that the theoretical development did not exactly explain burst test results in terms of peel test values. The test results demonstrate that even though the peeling times for the peel and burst tests were controlled to be the same, the theoretical formula (P,=,2 S/D) tends to overestimate the burst pressure. The overestimation increases at smaller gaps. These results are an indication that the formula is not universal and they suggest that it is an oversimplification. It might work for some materials at a particular set of testing conditions but not for others. Copyright © 2001 John Wiley & Sons, Ltd. [source] Cover Picture: Plasma Process.PLASMA PROCESSES AND POLYMERS, Issue 1 2007Polym. Cover: The combination of atmospheric pressure glow plasma fluorination and surface roughening is effective in the formation of highly releasing surfaces. A 180° peel test with an acrylic pressure-sensitive adhesive tape presents this evidence. Further details can be found in the article by Y. Masutani,* N. Nagai, S. Fujita, M. Hayashi, M. Kogoma, and K. Tanaka on page 41. [source] Adhesion of thermoplastic elastomer on surface treated aluminum by injection moldingPOLYMER ENGINEERING & SCIENCE, Issue 8 2007P.A. Fabrin Hybrid composites were prepared using insert injection molding without preheating. Thermoplastic elastomer (TPE) was overmolded on etched aluminum sheets having porous surface to provide large contact area between insert and TPE. The resulting bond strength was studied using a 180° peel test. The effect of aluminum microstructure and various processing steps of the surface treatment procedures on adhesion were studied. Maximum peel strength obtained was 9.33 N/cm using P2 treatment with alkaline-acid pretreatment. Lowest peel strength of 1.68 N/cm was achieved by alkaline,acid treatment. Increasing insert thickness lowers the peel strength since large heat capacity of thicker insert cools the melt and limits penetration of the melt to insert microcavities. At certain insert thickness microcavities are impregnated by the melt and no additional effect can be obtained by decreasing the insert thickness. POLYM. ENG. SCI., 47:1187,1191, 2007. © 2007 Society of Plastics Engineers [source] On the peel behavior of polymer coating,steel system: Effect of hygrothermal agingADVANCES IN POLYMER TECHNOLOGY, Issue 3 2010N. Guermazi Abstract This paper describes the development and application of a new peel protocols for the evaluation of adhesion of a flexible-to-rigid assembly. The developed apparatus allows simulating and predicting the delamination of the polymer coating from the steel substrate. The effect of certain test parameters such as a peel angle and peel speed was discussed. The durability of the retained assembly was equally investigated by considering an accelerated hygrothermal aging. The interfacial damages after conditioning and peel tests were characterized. Using two peeling angles of 90° and 180°, no significant difference was observed in terms of peel responses. The interface behavior seems to be not sensitive to the peel angle. However, an increase in the peel rate induces an increase in the peel strength. The characterization of the interface exhibits two mechanisms: The delamination process of the polymer coating is characterized by cohesive and mixed rupture, respectively, at low and high peel rates. Studying the effects of aging and coating defects on the interface behavior displays a continuous loss of adhesion of the polymer coating especially when it presents physical defects. © 2010 Wiley Periodicals, Inc. Adv Polym Techn 29:185,196, 2010; View this article online at wileyonlinelibrary. DOI 10.1002/adv.20188 [source] Effect of Oxygen-Absorbing Packaging on the Shelf Life of a Liquid-Based Component of Military Operational RationsJOURNAL OF FOOD SCIENCE, Issue 4 2009Carmen Gomes ABSTRACT:, Oxygen within the sealed package can reduce the quality of liquid-based food products with high oil content such as hot-filled meal-ready-to-eat (MRE) cheese spread, a component of military operational rations. The aim of this study was to test a novel oxygen absorber-containing laminate material and its ability to maintain and/or extend shelf life of a cheese-spread MRE item. An iron-based oxygen absorber (ABSO2RB®) activated by moisture was incorporated into the laminate and used to pack hot-filled cheese spread MREs. The kinetics of oxygen absorption due to humidity and temperature were characterized and peel tests performed to ensure pouch seal integrity. Accelerated shelf-life tests of ABSO2RB and regular MRE pouches without the O2 -absorber were conducted for 3 mo at 51.7 °C (125 °F), and 6 mo at 37.8 °C (100 °F) by measuring oxygen concentration (Mocon O2 -analyzer), microbiological, and physicochemical quality characteristics, including color, texture, moisture, free fatty acid (FFA), pH, water activity, and vitamins and A. Pouches stored at 26.7 °C (80 °F) for 12 mo served as calibrated controls. Consumer tests were conducted in-house and a confirmatory sensory test was conducted at Natick by a trained panel using a 9-point hedonic scale. ABSO2RB-laminates maintain the same seal integrity and strength as those of the control samples. The headspace oxygen concentrations in these pouches reached (P < 0.05) < 0.5% in 11 d of storage at 26.7 °C (80 °F) and remained below this level throughout the storage period (1 y). No microbial growth (aerobic, coliforms, yeast, and molds) was detected (P < 0.05) for both packages. Overall, the ABSO2RB-pouches indicate an improved reduction in oxygen and vitamin C retention compared with MRE controls and maintained product quality (physicochemical and organoleptic). ABSO2RB-laminates met the accelerated shelf-life requirement of 1 mo at 51.7 °C (125 °F), and 6 mo at 37.8 °C (100 °F). This study clearly shows the benefits of using active packaging technology on retaining nutrition and prolonging shelf life of high-fat, liquid content MRE items. [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] | ||||||||||||||||