Modified peel test

Adhesion of Plasma-Sprayed Hydroxyapatite Coatings 7.5.2.1 Modified Peel Test According to ASTM D3167-10... 

Tanknoto, Y Saeki, H. Kimoto, S. Nishiwaki, T. Nishiyama,N. Evaluation of adhesive properties of three resilient denture liners by the modified peel test method. Acta. Biomater., 2009, 5(2), 764-769. 

The test methods presently used to evaluate the adhesion of pressure-sensitive adhesives to release liners are modified adhesion tests, such as the 180° or 90° peel test, with the liner adhered to a test panel, or a T-peel test, where the sample is freely suspended while the tape is peeled at a controlled rate from the release liner. The values obtained by the latter method are alfected considerably by the stiffness of the liner, which alters the angle of peel. 

Bonding agents after manufacture are screened with a series of tests involving peel tests and exposure to hot water. These involve the use of the ASTM D429-99B Peel (modified... 

Additional data should be obtained with a cationic, and anionic styryl-functional silanes on a filler in a rubber that shows true adhesion (cohesive failure) in peel tests on glass to determine the ultimate effect of adhesion on reinforcement. Data of Tables 1 and 2 suggest that the iso-thiuronium chloride, and the vinylbenzyl functional silanes should be considered generally along with amine and mercaptan-functional silanes in modifying mineral fillers for rubbers. 

Most adhesive tapes are composed of a flexible backing (paper, plastic, cloth, metal foil, etc.) to which a pressure-sensitive adhesive has been applied to one side (both sides for double-sided tapes). Pressure-sensitive adhesives typically consist of a rubbery material with a modifying tactifier that may be applied to the tape by a solvent system, hot melt, or by other means. One would expect such materials to be sensitive to the mode of stress (tensile versus shear) in the region where debonding occurs. Furthermore, since tacky rubbers of the type used in pressure-sensitive adhesive are viscoelastic, one would anticipate material properties to be time- and rate-dependent. Are these expectations consistent with the observations from your simple peel test ... 

Table 14.3 contains data that compares the results of plasma treatment and sodium etching for four fluo-ropolymers. Peel strengths of untreated and treated samples were measured by bonding them into T-peel specimen using the flexibilized epoxy adhesive Scotch-Weld 3553 (available from 3M Corp.). The laminates were cured for several hours at 70°C and peel tested at 12.5 cm/min pull rate. Polytetrafluoroethylene does not accept plasma treatment as well as PEA and FEP, as indicated by its relatively low peel strength. Sodium etching is the only effective method of modifying the surface of PTFE. 

Adhesives - determination of firee monomer content in adhesives based on synthetic polymers Stmctural adhesives - T-peel test for fiexible-to-flexible bonded assemblies (ISO 11339 1993 modified)... 

Clearly, while comparative measurements can be made using the above types of peel test, the results obtained will depend upon such factors as the mechanical properties of the peel arms, their thickness, and also upon such factors as the applied peel angle, and the effective local peel angle at the peel front. Also, in a study to evaluate these different types of peel test, Kawashita and coworkers (2005) demonstrated that in tests such as the floating roller peel test, frequently the peel arm does not conform to the roller geometry. This was identified using a modified and partially cutaway apparatus, which allowed the conformation to be evaluated. 

The lap-shear and 180° peel test performance of very soft acrylic adhesives modified with nanoclay or silica nanoparticles were improved by the addition of nanoparticles (Patel et al. 2006). The addition of 6 wt% of nanoclay or 50 wt% of silica increased the peel force by about 40%. 

Note that studies made with the original unmodified polyphenylene oxide etched in the above solution for 3 min at 65 °C have revealed that chromic acid solution becomes ineffective after its first use. The evaluation was made with AF-30 nitrile-phenolic adhesive and modified T-peel tests. If it is desired to avoid this possible problem, vacuum blasting, followed by an acetone wipe, can be used. ... 

As stated earlier, adhesion is a major concern in electronic applications involving thin polyimide films either coated on hard substrates or laminated with metal ribbons. In these cases, neither lap-shear nor die-shear techniques allow the determination of the adhesion strength this can be done by using either the 90° peel test or the island blister test whose principles are sketched in Figs 12.26 and 12.27. The 90° peel test provides reliable data for the measurement of practical adhesion, especially useful for comparing the effect of surface treatments on the interfacial adhesion. The standard peel test procedure has been modified to determine the adhesive strength of thin polyimide films coated onto 10-cm silicon wafers. The equipment illustrated in Fig. 12.26 maintains a 90° peel effort during the test conducted at room temperature with a constant rate of crosshead displacement of 2 mm min . ... 

Delamination was carried out with a modified T-peel test (ASTM D1876). Strips 6.4 mm wide and 20 cm long were cut from the center of the tape and notched by pushing a fresh razor blade into the midplane of the tape. The notch was examined with an optical microscope to ensure that the crack started along a single interface. Specimens were peeled at ambient temperature at 10 mm min in an MTS Alliance RT/30 electromechanical testing frame. Three specimens of each composition were tested. 

An example of this improvement in toughness can be demonstrated by the addition of Vamac B-124, an ethylene/methyl acrylate copolymer from DuPont, to ethyl cyanoacrylate [24-26]. Three model instant adhesive formulations, a control without any polymeric additive (A), a formulation with poly(methyl methacrylate) (PMMA) (B), and a formulation with Vamac B-124 (C), are shown in Table 4. The formulation with PMMA, a thermoplastic which is added to modify viscosity, was included to determine if the addition of any polymer, not only rubbers, could improve the toughness properties of an alkyl cyanoacrylate instant adhesive. To demonstrate an improvement in toughness, the three formulations were tested for impact strength, 180° peel strength, and lapshear adhesive strength on steel specimens, before and after thermal exposure at 121°C. 

Under the best of conditions, single lap joint samples do not fail in pure shear due to the tensile and peel forces present at the ends of the overlap. These non-shear forces are exacerbated when using thin gauge adherends. Because of this, the lap joint dimensions as well as the testing rate were modified from the ASTM D-1002 standard as a result of earlier work on thin gauge steel adherends. 

Several TLC methods have been widely used to quantitatively estimate the flavonoids for quality control purposes rather than to detect adulteration. The potential exists, however, for testing authenticity. Naringin is an important compound in grapefruit juice, since it is largely responsible for the bitter character of the juice. Fisher et al. (121) developed a TLC procedure for naringin estimation. This was later modified by Tatum and Berry (122). Swift (123) developed a TLC-spectrophotometric assay for the neutral methoxylated flavones in orange peel. The method was subsequently expanded to the determination of these compounds in orange juice (124). 

The majority of carotenoids tested in this study increased the rhodamine accumulation of the Colo 320 MDR/MRP human colon cancer cells by the inhibition of the MDR1-mediated efflux pump activity. The cell size and the intracellular or sub cellular structures of carotenoid-treated cells were not modified during the short period of the flow cytometric experiments. The mean fluorescence and the shift of the fluorescence peak increased to various extents in the presence of carotenoids. The most active compounds were antheraxanthin, violeoxanthin, apple peel phytox-anthin, lutein and violaxanthin, while the luteoxanthin, neoxanthin and /f-cryploxanlhin were only moderate in their inhibition of the efflux pump (Tables 7, 8). 

Initially, pectinases were evaluated for peeling and segmenting activity at equivalent protein levels, using the Lowry procedure as modified by Potty (5) for protein determination. In later work, pectinases were tested at a number of concentrations to determine the amount required to yield a specific peel rating using regression analysis. 

We have applied a modified odor unit equation for evaluating aroma quality of the volatiles of Citrus sinensis OSBECK, ev. Shiroyanagi. Although the concept of odor units in flavor research was proposed by Rothe et al. (9) as a objective index of aroma quality, the concentration of individual components in a food (Fc in equation [1]) depends on the extraction efficiency of the essential oils. If the test sample is a solid, we can not calculate the exact concentration. Because the aroma oils, for example, may exist in different cells in the peels of citrus, we cannot take out only specified cells. It does not give a homogeneous concentration. Therefore, the odor units of individual aroma components in a food do not always give a constant value. Equation [1] should be applied to beverages such as apple juice, citrus juice, coffee, milk and so forth. The modified odor unit equation (75) for liquid and solid samples is shown as follows ... 

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