Peel strength different metals

Figure 1. Peel strengths of different metals adhered to PTFE, FEP, and PFA fluorocarbon polymer films. (Reprinted with permission from Chang, C.-A. et al. J. Vac. ScL 1990, 8(4), 3306. Copyright 1990 American Institute of Physics.)...

The same consideration of electronegativity also gives some correlation with the differences among the metals. The electronegativities are 1.5, 1.5, 1.6, 1.9, and 2.4 for Ti, Al, Cr, Cu, and Au, respectively (8). The peel strengths are the highest for Ti, followed by Cr, and the lowest for Cu and Au. The two exceptions are Al and Au/PFA. More study is needed to fully understand the differences among the metals studied here. 

Figure 6. Peel strengths of diHerent metals on mixed PTFE and PFA, heated to 375 C for different lengths of time.

The thermal treatments of the metal/fluorocarbon polymer systems show both stable structures and enhanced peel strengths. Such information is important to the application of fluorocarbon polymers to the packaging uses. Differently enhanced adhesion is noted for samples using mixed polymers, which may serve further purposes to technologies depending on the specific uses. 

Resins. Because of colloidal incompatibility, the metal oxide/r-butyl phenolic resin complex which in solvent adhesives provides improved adhesion largely and hot strength is ineffective in latex systems. Of the types of resins which are commonly used in Neoprene latex adhesives, only the terpene phenolics such as Durez 12603 (Occidental) and SP-560 (Schenectady) do not cause an appreciable loss in hot strength as the resin content is increased. Others such as coumarone indene resins, liquid terpene resins and rosin esters are valuable from a standpoint of increasing adhesion and open time, but decrease cohesive strength at elevated temperatures. This is illustrated in Fig. 8, where canvas-to-canvas peel strength at 70°C (158°F) is plotted against resin level with several different classes of resins in Neoprene Latex 750. Only the terpene phenolic systems provided adhesive failure, even at the 50 phr... 

The different bond test methods yield results that do not always correlate closely in terms of bond strength or mode of failure [22]. Some of these contrasts in results reflect substantial differences in the manner in which the rubber to metal bond is stressed. This is likely to be more meaningful for some actual applications of bonded parts and less for others, depending on how the bond is stressed in such applications, e.g., shearing, tension or peeling. 

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