Peel work

Figures 22.5 and 22.6 show how the two peels work together and how often they should be repeated.

SIZING AGENT PEELING WORK COBB VALUE... 

It is unknown how a superficial peel working on epidermis could have effects on derma too. It has been proposed that this process could be based on growing factors as keratinocytes TGF-f) and their transduction signals. This is a new research field on the science of chemical peels. 

Work of Electrical Double Layer versus Peel Work... 

On the other hand, the actual peeling of the LDPE film from the aluminum foil yields a specific peel work of 1 J/m, which is about 600 times that of the Thus, the specific peel energy is much larger than the stored electrostatic energy due to the presence of the EDL. This is an indication that the electrostatic component is only a fraction of the total adhesive strength. Thus, this result still cannot serve as definitive proof for Deryagin s hypothesis on the dominant role of EDL in adhesion. 

HOW THE MOST COMMONLY USED SUBSTANCES IN CHEMICAL PEELS WORK-A PROPOSAL FOR CLASSIFICATION ... 

Fig. 8. (a) Positive proofing image formation (b) positive working dry peel-apart process and (c) peel-apart process. 

Based on the arguments presented thus far, it would seem that, for a given PSA, the work of adhesion, and thus the peel force, should decrease systematically as the surface energy of the release coating is decreased. Therefore, fluorochemical containing polymers should provide the lowest release forces. In practice, these generalities often do not hold, due to other factors, such as interfacial dynamics and rheological considerations. 

The dependence of release force on the flexibility of the release layers is noted in systems other than silicones. Recent work in olefin release shows that release is a strong function of the density or crystallinity of the layer [44], At a density above 0.9 g/cm release for an acrylate PSA is greater than 270 g/cm. However, when the density of PE is dropped to 0.865 g/cm-, the release force of the same adhesive construction drops to 35 g/cm. An investigation of interfacial friction and slip in these systems has not yet been reported, but again the manipulation of release rheology greatly impacts the measured peel force. 

Fig. 35. OSEE response and peel strength of NBR rubber on steel for HD2 grease (data from Ref. [162]) and silicone release agent contamination (data from R.L. Cause, unpublished work and Ref. [10]). The HD2 grease is slightly photoemitting so the OSEE signal does not decrease to zero at high contamination levels.

Figure 19. (1) Oxidized polypyrrole (PPy) film electrogenented on a steel electrode. (2) A tape was fastened to the dry polypyrrole film (A). B is doublesided tape and C is a protective sheet of paper. (3) The bilayer device with a protective film is removed from the electrode. (4) The protective sheet is peeled off and the bilayer is ready to work. (Reprinted from Handbook of Organic Conductive Molecules ami Polymers, H.S. Nalwa, ed.,Vol. 4,1997, Figs. 10.13, 10.15a, 10.18, 10.36. Reproduced with permission of John Wiley Sons, Ltd., Chichester. UK.)...

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