Peel-pull test

The peel-pull test is used to determine the level of adhesion retained as a result of permeation and absorption testing (Fig. 4.3). ASTM C865 is typically used to determine the peel strength on a 2.5 cm (1 inch) wide strip. Data are reported in pounds of force per inch of width. A good number is 50 Ibf/in although lower numbers of 10 Ibf/in are acceptable in some cases. The number is also compared to that obtained either on an unexposed panel or on the same panel outside the exposed ring. 

Figure 4.3. Peel pull test on an Atlas cell panel. Courtesy DuPont Engineering Technoiogy.)...

The spark test is carried out for pinholes or breaks in the welds as a result of exposure. Depending on the thickness, the voltage used can be anywhere from 5000 to 15,000 V. The scribe test is used for coatings where peel-pull is not possible. It is qualitative and compares the adhesion of the exposed surface to that outside the exposed area. Results are used for comparison only. 

After a dwell time of five seconds under the device, it can be seen in Figure 7.10 that the shear strength of the bond between the LPDE sample and cyanoacrylate adhesive increased 10-fold, and the shear strength of the bond between the LPDE sample and the light cure acrylic adhesive increased 40-fold. Subsequently, MIL-STD-883 Method 2011.7 was applied as a destructive bond pull test to evaluate bond strength and bond strength distribution of various surface contaminations after CO2 treatment. The apparatus used had an accuracy of 5% and performed at a 90° peel angle. 

Both static and dynamic tests are employed to evaluate the adhesion strength of cord-mbber composites. The major static tests used in tire industry are H-adhesion, 90/180° peel test, tire cord adhesion test (TCAT) and co-axial shear pull-out test (CSPT). Although these methods are... 

Print adhesion on plastics (and foil) is normally checked using a self-adhesive tape peel test. A few inches of a suitable standard tape is firmly pressed onto the print area then pulled off, slowly at first, then more rapidly. An assessment of print adhesion can be made from the quantity (ideally none) removed. Adhesion can vary according to the type and colour of the ink, the degree of pretreatment, the surface involved and the printing process, etc. In order to test print under likely use conditions, product immersion tests may be necessary 60°C (140°F) is a frequently used condition, for 3 to 6 h. If product-pack may be used with soapy hands, a solution of soap can be employed. A print adhesion test, as above, can then be carried out, on the washed material, after it has been cooled to room temperature. 

Scotch-tape test [13,16-20] Abrasion test [18,21] Bend and stretch test [15,22] Shearing stress test [22-24] Direct pull-off method [15,25-39] Moment or topple test [40-43] Electromagnetic tensile test [44] Laser spalation test [45] Ultracentrifuge test [13,22,46-50] Ultrasonic test [13,76] Peeling test (13, 51-54] Tangential-shear test [55,56] Scratch test [50,52, 57-73]... 

According to the peel test, the sample is attached to a movable crosshead via grips or clamps. The test speed is kept constant, typically at 10 or 12 in/minute and the sample pulled until separation or break occurs. Most peel tests require a load of 10 pounds or less. The peak load at separation, average load, and energy at break are measured and stored in the equipment s controller memory and subsequently transferred to a computer where loads are plotted versus time. Test methods and standards include ASTM D903-98 and ASTM D3807. 

One of the simplest peel tests to conduct is the 180° peel test described in ASTM 903, Standard Test Method for Peel or Stripping Strength of Adhesive Bonds. In this test, one adherend is much more flexible than the other, so that upon gripping and pulling the two unbonded ends, the sample assumes the configuration shown in Fig. 8d. 

Table 3.8 shows the results of the static bending tests, the relative elongations of the metal substrate at which the fibers of the glass cloth broke and wrinkles and folds appeared on its external siuface. The flexural tests indicated that in the case of the pulled fibers, the threads of the glass cloth broke in the csise of the pushed fibers, wrinkles and folds appeared on the external layer of the glass cloth while the inner layers were firm on the metal surface. The static tests of the specimens with the metal base extension showed that the glass-reinforced plastic peeled off the metal for stress in the metal not less than 355 MPa. 

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