Low-Temperature Plasma Modification of Styrene–Butadiene Block Copolymer Surfaces for Improved Adhesion—A Kinetic Approach

Abstract

This paper proposed a kinetic model that can describe the changes in the adhesion properties of styrene–butadiene (SBS) block copolymer surfaces under the influence of low-temperature plasma treatment. As a measure of these changes, the peel strength of joints formed between the copolymer surface and the polyurethane adhesive was chosen. Five types of low-temperature low-pressure RF plasma, two inert plasmas (Ar and He), and three reactive plasmas (O2, CO2, and CCl4) were tested. It was found that for all these types of plasma, the peel strength with the plasma treatment time first increases rapidly reaching a maximum value, and then there is a visible decrease in peel strength, after which the peel strength increases again. This dependence of the peel strength on the plasma treatment time is very well described by the proposed model, which considers three processes: (1) the generation of radical states followed by the creation of functional groups involved in the adhesive bonding process, (2) the surface cross-linking that decreases the concentration of these functional groups, and (3) the formation of nano-roughness. The model analysis revealed differences between the action of reactive and inert plasmas in the SBS surface cross-linking mechanism and preferential etching process, as well as differences in the generation of radical states between the O2 plasma (electron process) and other plasmas tested (ionic processes).

Effect of Carbon Black Nanofiller on Adhesion Properties of SBS Rubber Surfaces Treated by Low-Pressure Plasma

“…In our case, however, under the used plasma parameters and plasma treatment times as short as 2 min, the effect of the nano-roughness generated by plasma treatment on the joint strength can be negligible compared to the process of chemical bond formation. This is supported by investigations performed by AFM microscopy for plasma-treated SBS surfaces [32]. The general fact that nano-roughness formation is more intensive for higher discharge power [33] also does not confirm in our case the contribution of this effect to the adhesive bonding process-as shown in Figure 1, the peel strength for 50 W is greater than for 80 W.…”

Anti-Mold Protection of Textile Surfaces with Cold Plasma Produced Biocidal Nanocoatings

“…Such an effect, however, is justified by taking into account the dependence of the grafting process efficiency on the concentration of radical states generated on the surface. As the concentration of the radicals increases, they recombine more easily, which ultimately leads to a decrease in this concentration [ 43 , 44 ], and thus also to the lower activation of the grafting process. In turn, the analysis of the grafting time ( Figure 5 c) shows that the process is heading towards a termination state, which is probably mainly due to cross-linking between growing poly(allylamine) chains.…”

Effect of low‐pressure cold plasma on the properties of edible film based on alginate enriched with Dunaliella salina powder

“…The formation of the functional group by plasma treatment depends on a number of created radical states on film surfaces and the concentration of radical states in reactive and inert plasma, respectively. [ 65 ] The formation of C–O–C bridges as a result of the cross‐linking process causes changes in the hydroxyl functional group, which are expressed in Figure 4 (in the range of 3600–3700 and 990–1130 cm −1 , which are attributed to O–H and C–O–C stretching vibrations, respectively). [ 65 ] It is noteworthy that the surface to bulk functional group migration may induce changes in surface physical properties and wettability.…”

“…[ 65 ] The formation of C–O–C bridges as a result of the cross‐linking process causes changes in the hydroxyl functional group, which are expressed in Figure 4 (in the range of 3600–3700 and 990–1130 cm −1 , which are attributed to O–H and C–O–C stretching vibrations, respectively). [ 65 ] It is noteworthy that the surface to bulk functional group migration may induce changes in surface physical properties and wettability. [ 64 ]…”