Adhesive strength Peel test

Test Value Adhesive Strength Peel Force Peel Force ... 

Peel or Stripping Strength of Adhesive Bonds, Test for (D 903) Climbing Drum Peel Test for Adhesives, Method for (D 1781) Peel Resistance of Adhesives (T-Peel Test), Test for (D 1876) Evaluating Peel Strength of Shoe Sole Attaching Adhesives,... 

Even if no values for peel strength are measured, this peeling test shows very sensitive adhesion or cohesion failure, which sometimes are the only criteria to be checked. Remember, the mechanical values of the adhesive can be determined by other methods. If cohesion failure occurs, the result is generally good. If there is an influence of humidity and temperature on the adhesion, this peeling test will usually show it. 

The adhesion-in-peel test was used to determine peel strength and adhesion characteristics of a cured-in-place silicone elastomeric joint sealant on aluminium substrates. The sealant used was Dow Corning Type 3145 RTV Adhesive Sealant. The results showed that the silicone sealant had poor adhesive bonding to the untreated aluminium. Plasma polymerisation of hexamethyl-disiloxane(HMDS) onto the aluminium was shown to move the locus of adhesive failure to between the plasma film and the silicone. Plasma polymerisation of HMDS... 

The routine compositional and functional testing done on the adhesives includes gas chromatographic testing for purity, potentiometric titrations for acid stabilizer concentrations, accelerated thermal stabiUty tests for shelf life, fixture time cure speed tests, and assorted ASTM tests for tensile shear strengths, peel and impact strengths, and hot strengths. 

Fig. 1, Schematic of commonly u.sed methods for testing the strength of adhesive joints, (a) Peel test. Note that the peel angle can be changed depending on the test requirements, (b) Double overlap shear test. In this test, the failure is predominantly mode II. (c) Single overlap shear test. In this test the failure mode is mixture of mode I and mode II. (d) Blister test.

Fig. 17. Adhesion energy G measured as a function of the surface density of the interfacial chains. It may noted that the strength measured in a peel test (a) is about 5 times larger than that measured using the JKR method (b). Further, a maximum exists in the value of G as function of the surface chain density. This is because of swelling effects at larger values of surface chain density. The open symbols represent the data for elastomer molecular weight Mo = 24,000 and the closed symbols represent the data for Mo = 10,000.

Adhesive strength refers to the bond produced by contact of an adhesive to a surface. It used to be measured by peeling tests. This ultimate strength depends on temperature, applied pressure and time of contact. 

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. 

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... 

The interaction of two substrates, the bond strength of adhesives are frequently measured by the peel test [76]. The results can often be related to the reversible work of adhesion. Due to its physical nature such a measurement is impossible to carry out for particulate filled polymers. Even interfacial shear strength widely applied for the characterization of matrix/fiber adhesion cannot be used in particulate filled polymers. Interfacial adhesion of the components is usually deduced indirectly from the mechanical properties of composites with the help of models describing composition dependence. Such models must also take into account interfacial interactions. 

In the literature, there are several reports that examine the role of conventional fillers like carbon black on the autohesive tack (uncured adhesion between a similar pair of elastomers) [225]. It has been shown that the incorporation of carbon black at very high concentration (>30 phr) can increase the autohesive tack of natural and butyl rubber [225]. Very recently, for the first time, Kumar et al. [164] reported the effect of NA nanoclay (at relatively very low concentration) on the autohesive tack of BIMS rubber by a 180° peel test. XRD and AFM show intercalated morphology of nanoclay in the BIMS rubber matrix. However, the autohesive tack strength dramatically increases with nanoclay concentration up to 8 phr, beyond which it apparently reaches a plateau at 16 phr of nanoclay concentration (see Fig. 36). For example, the tack strength of 16 phr of nanoclay-loaded sample is nearly 158% higher than the tack strength of neat BIMS rubber. The force versus, distance curves from the peel tests for selected samples are shown in Fig. 37. 

When using peel tests on such products as belts to separate the plies, it can be difficult to obtain interfacial failure. Loha et al47 successfully used test pieces including a perforated metal sheet at the interface to measure rubber to rubber adhesion strength. 

Adhesion strength of polymeric coatings using 180° peel test... 

Test Method for Adhesion in Peel of Elastomeric Joint Sealants Recommended Practice for Surface Preparation of Concrete for Application of Chemical Resistance Resin Monolithic Surfaces Method of Testing Release Papers Used with Preformed Tape Sealants Test Method for T-Peel Strength of Hot Applied Sealants Test Method for Tensile Adhesive Strength of Preformed Tape Sealants by Disk Method... 

Fig. 11. Normalised enhanced adhesive strength wyw as a function of the surface density, a, for two PDMS elastomers in contact with silicon wafers covered with irreversibly adsorbed chains. Wis the thermodynamic work of adhesion, W=2y, with ythe surface tension of PDMS, 7=21.6 mN m"1 at 25 °C. The filled symbols correspond to a molecular weight between crosslinks in the elastomer Mc=24.2 kg mol-1 while Mc=10.2 kg mol-1 for the open symbols. The adhesive strength, G, has been measured by peel tests performed at a very low velocity of the propagation of fracture, 0.17 im/s. The molecular weight of the surface anchored chains is Mw=242 kg mol-1...

Fig. 16. Universal curve giving the enhanced adhesive strength, G-W, normalized by the optimum enhanced adhesive strength, Gopt-W, as a function of the normalized surface density, G/aopt (o0pt is the surface density leading to the maximum adhesive strength) for different irreversibly adsorbed PDMS layers in contact with PDMS elastomers. Peel tests with a fracture velocity of 0.017 pm/s have been used to measure G. The molecular weights of the surface chains, Mw and the molecular weights between crosslinks of the elastomers, Mc, are the following ...

An important question is now to understand how these two effects, adhesion enhancement and adjusted friction, can interplay. For example, when peel tests are used to estimate the adhesive strength, the curvature of the peeled ribbon implies a fracture advancing through both modes I and II of opening [72,155]. This means that in the presence of surface anchored chains, the connector... 

---