Glass peel tests

E-glass were random sizes unsuitable for peel tests. Pyrex and quartz bars were 127 x 25 x 6.5mm. 

Coating with Bulk Polybutadiene. E-glass fabric was embedded In Firestone s Diene 35 NFA using procedures very similar to those used to prepare peel test specimens. Rubber, which had been mill-mixed with 0.05% dlcumyl peroxide, was premolded between Mylar sheets to the desired thlckness(0.308, 0.151, or 0.100 cm) and size ( 30.5 X 18 cm) by molding for 1 hour at 60 C. and 40,000 lbs/5" ram. Fabric was cut so that the final size was at least one Inch smaller than the rubber sheets In all directions. A sandwich was made from the fabric and two premolded rubber sheets of the same thickness and about half the total thickness of the final sandwich. The sandwich was cured In a press for 2 hours at 150°C and 5000 lbs/5" ram. In the cured specimen the fabric was embedded In the center of the molded specimen (0.15 -0.40 In thick). Samples were Immensed In alkali before cutting to size for tensile tests. 

Figure 4. Peel test results on E-glass plates as a function of percent of 3-aminopropyltrlethoxysllane in solution used to treat plates, x results after immersion in alkali for 7 days at 80"C. o initial results.

Later, McPherson (39) demonstrated that the Inclusion of a CTBN/liquid epoxy adduct enhanced both the flexibility and adhesion of a dimer acid flexibllized epoxy/brominated epoxy mixture when cured with a combination of chlorendic and nadic-methyl anhydrides. With an epoxy-glass laminate as substrate, such mixtures were coated at 0.5-2.0 mils thickness, cured, sensitized and copper plated (1.5 mils) by an electroless process. 90 peel testing (2 inches/mln. rate, 25 C) gave 14.0 pli peel force where 5.0 pli is considered normal. 

Another similar test is the peel test [11]. A strip of self-adhesive material is peeled off the substrate and the force needed for peeling is recorded. In order not to tear the rubber during the peeling test it is reinforced with a glass fabric. 

In some circumstances, parallel curves are not obtained in such plots. This occurs when <1> becomes strain dependent and typically happens near the glass transition(9) or as loads become large. It can also happen if the volume of deformed material changes significantly from one test to another, as when peel testing is carried out at very low angles of peel. Although the... 

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. 

D-0903. Test Method for Peel or Stripping Strength of Adhesive Bonds. This is the standard 180 peel test (Fig. 12) applicable where one of the adherends is sufficiently flexible to endure the 180° fold back. Tests the resistance to peel separation of flexible foils, films, or tapes from relatively rigid base adherends (metal, wood, plastic, glass, etc. of adequate thickness). 

In order to understand and avoid lot-to-lot variations within the tape rolls, the ASTM standard advises that a peel test be performed on a tape lot at the start of the testing. This peel test is performed by adhering the tape to a smooth and hard surface such as a glass surface. Next, the peel force is measured using an Instron by pulling the tape from the flat surface at either 90° or an 180° angle. 

In addition to these types of tests, many vendors conduct standard physical tests on their products, such as tests for tensile strength and peel strength. Tensile strength indicates the strength per area of material, while the peel strength indicates the force it would take to peel the product from the glass surface. Several vendors indicate that their products exceed American National Standards Institute (ANSI) standard Z97.1 for tensile strength and adhesion. 

After the breakage of the test piece, it is not only interesting to know the average peel force for the calculation of the peel ressitance it is just as important to determine the causes of the break in the bonded joint If possible, a fracture analysis is carried out for this purpose by means of a microscope or magnifying glass. There are three different possibilities for fractures adhesion, cohesion or mixed fracture (Figure 10.7). 

Sample preparation. Kiwifruit purees were prepared from the hand peeled fruit in a 1°C room after removal of seeds anmd cores. The product was homogenized in a Waring blender, and frozen immediately in sealed glass jars at -26°C. The frozen purees were thawed and mixed thoroughly before analysis. For the nectars, four representative cans were tested for each sample and the average values are reported. 

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