Testing adhesion

Testing of Painted Products. The enhancement of paint adhesion is one of the principal functions of conversion coating (20—22). A group of tests based on product deformation is used to test the painted product. The appHance and cod-coating industries use the mandrel bend, the cross-hatch adhesion test, and the direct and reverse impact tests. Adhesion after a water soak is judged using a cross-hatch test performed on the exposed surface. 

A sealant s adhesion is commonly studied by 180 degree peel tests such as ASTM C794 or by tensHe/adhesion joints tests such as ASTM C719. The adhesion test protocol should simulate actual field conditions as closely as possible. Sealants often have good adhesion to dry substrates, but this adhesion may be quickly destroyed by water. Because most sealants are exposed to water over their lifetime, adhesion testing should include exposure to water for some length of time. ASTM C719 is one of the better tests to determine a sealant s adhesion durabHity as it exposes sealants to seven days of water immersion. 

Static Adhesion Tests for Organic-Based Yarns, Cords, and Fabrics. The most commonly used static adhesion tests are the H-test... 

Barquins, M. and Maugis, D., Tackiness of elastomers. J. Adhes., 13, 53-65 (1981). Creton, C. and Lakrout, H., Micromechanics of flat-probe adhesion tests of soft vi.scoelas-tic polymer films. J. Polym. Sci. B Polym. Phys., 38(7), 965-979 (2000). 

Changes observed in the composition of the rubber/brass interphase correlated well with results of adhesion tests carried out on brass-plated steel wires embedded in blocks of rubber [46]. The force required to pull the wires out of the blocks decreased steadily as vulcanization temperature increased. This effect was especially pronounced when the specimens were aged at elevated temperature and humidity for several days before the wires were pulled out of the rubber blocks. 

There is second shear adhesion test that is now being reported with increasing frequency, the so-called SAFT, or shear adhesion failure temperature test. It is particularly popular among block copolymer PSA developers. In this test [15], a shear specimen with an overlap area of 2.54 cm x 2.54 cm is prepared and suspended in a circulating air oven. A 1-kg weight is attached to the tape and the oven temperature is raised continuously 5.5°C per 15 min until failure. An industry wide standard has not yet been written for this test. 

Fig. 2. Adhesion tests after thermal exposure with ECA crosslinked with the dicyanoacrylate ester of butanediol, 7.

This phenomenon can be demonstrated by both measuring the changes of the thermal properties of the ECA homopolymer and in adhesion tests. The addition of only 1 wt.% of 9 to a sample of the ECA homopolymer significantly increases the onset of decomposition in the thermogravimetric analysis (TGA) of the polymer, as seen in Fig. 9 [29]. 

When required, perform adhesion tests, curing tests or tests for surface contamination. 

The practical result of epitaxy is a very high degree of adhesion between coating and substrate. The force needed to separate the interface is similar to that needed to break the metals on either side. Where a true metallic bond forms at an epitaxial interface it is only possible to measure adhesion if the bond is the weakest of the three near the interface. An adhesion test based on breaking the joint indicates only which of the three is weakest. For practical purposes any epitaxial joint will have a strength more than adequate for service conditions. 

The Underwriters Laboratories utilizes a combination of methods for environmental conditioning and adhesion testing to evalu-... 

Chitosan is the main structural component of crab and shrimp shells. Chitosan contains both reactive amino and hydroxyl groups, which can be used to chemically alter its properties under mild reaction conditions. Al-acyl chitosans were already reported as blood-compatible materials. UV irradiation grafting technique was utilized to introduce obutyrylchitosan (OBCS) onto the grafted SR film in the presence of the photosensitive heterobifunctional cross-linking agent. The platelet adhesion test revealed that films grafted on OBCS show excellent antiplatelet adhesion. 

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... 

FIGURE 12.20 Tire cord adhesion test specimens and scan area of fracture surfaces. (From Chandra, A.K., Mukhopadhyay, R., and Bhowmick, A.K., Polym. Test., 15, 13, 1996. With permission.)... 

FIGURE 23.17 Styrene-butadiene copolymer (SBR) peel adhesion test piece after first appl3nng a gas decompression (GD) procedure and then peel testing. 

There are some standard adhesion tests used by the paint and coatings industry, which we have adopted for our work. The most common is the Scotch tape test, which is described by an ASTM D3359, method B. 

Thus SLA 1020 features a particular type of morphology, which we were targeting to manufacture in order to improve the packing density, the adhesion to the copper and the cycling behavior. The adhesion test of an electrode prepared with SLA1020 is presented by Figure 5. 

Table II. Adhesive test results for 3 1 blend of 4-allyloxstyrene/DVE-3...

For the balanced beam-scrape adhesion test, ASTM-2197, weights were added to a commercial balanced beam tester. The kind of scratch produced by the stylus with the different loadings was recorded and served as a measure of film hardness. Coatings which are not scratched to bare metal by 500 g are desirable. 

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