Maximum bond strength

Fillers. Fillers are not commonly added to CR adhesives. Calcium carbonate or clay can be primarily added to reduce cost in high-solids CR mastics. Maximum bond strength is obtained using fillers with low particle size (lower than 5 [jim) and intermediate oil absorption (30 g/100 g filler). In general, fillers reduce the specific adhesion and cohesion strength of adhesive films. Although polychloroprene is inherently flame retardant, aluminium trihydrate, zinc borate, antimony trioxide or... 

It is seen that the maximum bond strength for set I (Powell s second set) is greater than that for set II (Powell s first set), and also that there is for each of the two kinds of functions great deviation from cylindrical symmetry. The values of the functions in the planes of symmetry are shown in Figures 2 and 3. Comparison with the corresponding cross sections for d2 and d,2-.2 shows that the functions I are qualitatively similar to d 2, and the functions II are more similar to dx2-t2. The values for the two functions are indicated in Figure 1. 

In the equation, Db, is the interfacial bond strength normalized with respect to the maximum bond strength in the composite and the integration variable, t, represents the time an incremental area came into intimate contact. 

Comyn [1] has pointed out that maximum bond strength and consequently greater adhesion between the substrate and polymer could be achieved with a monolayer of silane bound to both the adherend and adhesive. The current investigation was undertaken to evaluate the possibility of monolayer level depositions on silicon substrates by employing a few w -functionalized alkanoyl-substituted derivatives of APTES which will provide polar moieties as well. The interactions of these functionalized silanes covalently immobilized on silicon with octadecylamine and octadecanoic acid, used as models for basic and acidic polymeric adhesives, were also examined in this study. Characterization of the silanized surfaces as well as studies on their interactions with the above two chemical probes were carried out through ellipsometric and XPS measurements. 

Generally only solvent cleaning and abrasion are necessary for surface preparation of polystyrene parts. Methanol and isopropanol are acceptable solvents for solvent cleaning of polystyrene. For maximum bond strength the substrates can be etched with sodium dichromate-sulfuric acid solution at elevated temperature. Table 16.14 shows the results of a study on the durability of joints formed between polystyrene and aluminum with different types of adhesives exposed to different environments. 

The width of the lap shear specimen is generally 1 in. The recommended length of overlap, for metal substrates of 0.064-in thickness, is 0.5 + 0.05 in however, it is recommended that the overlap length be chosen so that the yield point of the substrate is not exceeded. In lap shear specimens, an optimum adhesive thickness exists. For maximum bond strengths, the optimum thickness varies with adhesives of different moduli (from about 2 mils for high-modulus adhesives to about 6 mils for low-modulus adhesives).5... 

Chromium Trichloroethylene 1. Abrasion. Grit or vapor blast, or 100-grit emery cloth, followed by solvent degreasing. 2. Etch for 1-5 min at 90-95°C in Suitable for general-purpose bonding For maximum bond strength... 

Use 320-grit emery cloth for foil For maximum bond strength. Suitable for brass and bronze. ASTM D 2651 sulfuric acid-dichromate-ferric sulfate etch... 

Acetal (homopolymer) Acetone 1. Abrasion. Sand with 280-grit emery cloth followed by solvent degreasing. 2. Satinizing technique. Immerse the part in the following for 5-30 s at 80-120°C Perchloroethylene 96.85 1,4 Dioxane 3.0 /7-Toluenesulfonic acid 0.05 Cab-o-Sil (Cabot Corp.) 0.10 Transfer the part immediately to an oven at 120°C for 1 min. Wash in hot water. Dry in air at 120°C. For general-purpose bonding For maximum bond strength. Recommended by DuPont... 

For maximum bond strength. Suitable for Mylar films... 

The sealing of corneal perforations using whole enucleated bovine eyes required the same attention to tissue preparation. The epithelial layer in the bond area was removed. After the puncture of the cornea, the stroma was rinsed and blotted to remove potentially interfering aqueous humor components. The Hy-pan hydrogel material, which is 80-90% water, was routinely presoaked in PBS. Maximum bond strengths using 53 /ig of MAP per cm2 patch were obtained in 10 min after application. 

Figure 6. Surface plots of the momentum density corresponding to two different hybrids of the form sp3db2. For the left plot, b = 2 (as in octahedral hybrids), for the right one, 6 = 5 (maximum bond strength). The surface plots are sections through the xz plane. Note that they both exhibit four points where the density vanishes exactly.

Acetal Copolymer (CELCON ) Two types of non-solvent adhesives are used, structural and non-structural. Most structural adhesives are based on thermoset resins and require the use of a catalyst and/or heat to cure. This type of adhesive is normally used in applications which require maximum bond strength and minimum creep of the adhesive joint under sustained loading. Many structural adhesives can be used continuously at temperatures up to 350 F, which is higher than the... 

Mixing ratio Ratio for the mixing of the adhesive components prior to processing, prescribed by the adhesive manufacturer. Very important to achieve maximum bond strength. 

The aforementioned diffuse-layer and discreteness-of-charge effects have been taken into consideration in the model proposed by Grahame and Parsons [26,250-252]. First, it was assumed (unlike in the Stern model) that the specifically adsorbed ions were located at the distance from the metal surface (in the inner Helmholtz plane ) ensuring their maximum bond strength, owing to the combination of forces of electrostatic and quantum-mechanical origins. It shows the need for the partial or even complete desolvation of the adsorbed species and its deep penetration into the compact layer. The position of this adsorption plane depends on all components of the system, metal, solvent, and adsorbed ion. 

Maximum bonding strength is not usually produced instantly. 

One useful property of cationic polymerization is that it is not air inhibited. In the absence of nucleophilic impurities, there are no inherent modes of termination. Thus, the polymerization may continue for long periods (hours to days) after the light is turned off, in contrast to photoinitiated free radical polymerization (24). This post-cure should be useful for laminating two opaque materials, in that irradiation of the adhesive followed by lamination should result in a well cured adhesive, although it may take 1-2 days to form maximum bond strength. 

To attain maximum bond strength with solvent-cemented Noryl joints, the manufacturer of the resin recommends the following steps ... 

Maintain uniform clamping pressure for 30-50 seconds, or as long as the particular part requires. Bonded parts may be handled safely after the original hold time, although maximum bond strength is usually reached at a later time (see Table 9.9). 

Time, joint conditioning— The time interval between the removal of the joint from the conditions of heat, pressure, or both, used to accomplish bonding and the attaimnent of approximately maximum bond strength. Sometimes called joint aging time. 

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