Page 70 - Handbook of Adhesion Promoters

4.2 Surface treatment 63

Figure 4.9. Water contact angle (a) and total surface energy (b) as a function of exposure time of the plasma on
PEEK substrate. [Adapted, by permission, from Dupuis, A; Ho, TH; Fahs, A; Lafabrier, A; Louarn, G;
Bacharouche, J; Airoudj, A; Aragon, E; Chailan, J-F, Appl. Surf. Sci., 357, 1198-204, 2015.]

ing and, therefore, bonding interface has to be sealed because it will not be resistant to
humidity. 18
Polydimethylsiloxane films were treated with either oxygen, nitrogen, or argon
19
plasma between 40 W and 120 W for 5 to 15 min. Oxygen and nitrogen plasma
increased adhesive strength due to a chemical interaction between functional groups cre-
19
ated on the surface. In contrast, the argon plasma increased roughness which increased
19
mechanical interlocking.
The atmospheric pressure air plasma torch treatment was used to remove lubricant
20
pollutants after machining processes of steel. Cleaning with torch removed about 90%
20
lubricant and caused better improvement of adhesion than cleaning with solvent.
Polyetheretherketone carbon fiber reinforced composites are highly suitable candi-
21
dates for replacement of metallic parts in the aerospace industry. Because of its poor sur-
face energy, PEEK requires a surface treatment to enhance its adhesion with the coating. 21
21
The atmospheric plasma treatment has been selected for the purpose. Figure 4.9 shows
21
the results of treatment. Nitrogen and air plasma treatments increase adhesion of epoxy
21
powder coating to PEEK-based composites.
The effect of argon plasma on surface modification of ultra high molecular weight
22
polyethylene textiles was studied. The surface roughness of UHMWPE textile was
22
increased and the contact angle was decreased from 80° to 28°. The peel strength of
UHMWPE textile/adhesive (PU) composites was increased from 0.6 to 4.6 kgf/in after the
22
argon plasma treatment with power of 40W for 5 min.
The adhesion promoter layer was deposited by metal chelating poly(4-vinylpyridine)
(P4VP) film onto various organic and inorganic substrates via chemical vapor deposition
process to enhance the adhesion between the electroless deposited copper layer and the
23
substrate. Figure 2.27 and description in the text close to the figure give information on
the process of formation of the intermediate layer which increased adhesion between sub-
23
strate and metal.
The adhesion of polypropylene films towards polar polymeric films was improved
by grafting with acrylic acid after activation pretreatments using γ-rays or argon plasma. 24
In spite of a peroxide concentration 100 times lower than after γ-irradiation and a percent-