Different Performance of Ar, O ₂ and CO ₂ RF Plasmas in the Adhesion of Thermoplastic Rubber to Polyurethane Adhesive

Hyperthermal Atomic Oxygen and Argon Modification of Polymer Surfaces Investigated by Molecular Dynamics Simulations

“…The treatment of polymer surfaces by ion‐beams or exposure to plasmas modifies their surface properties in order to form barrier coatings,1 improving adhesion,2–6 induce functionalization,7, 8 or sterilization,9 and augment biocompatibility 10. In the case of plasmas, these processes involve a complex series of interactions between electrons, photons, neutrals, accelerated particles, and the polymer surface that results in the chemical modification of the surface 11.…”

Improved Adhesion of RF Plasma Treated Rubbers by Isocyanate Incorporation to Polyurethane Adhesive

“…CO 2 plasma treatment notably enhances the adhesion even for short treatment times (2 min). T‐peel strength values are similar irrespective of the adhesive, therefore, increased adhesion must be due to the surface modifications produced by the plasma treatment on TR rubber4, 5 and the incorporation of isocyanate to the polyurethane adhesive does not further enhance adhesion.…”

“…CO 2 plasma produce ablation of rubber favoring the removal of low molecular weight anti‐adherent moieties form the rubber surface; oxidizes the rubber surface, increasing the wettability and the surface energy, and increase the roughness, favoring mechanical interlocking with the adhesive. Therefore, adhesion of rubber towards polyurethane adhesive is enhanced via these mechanisms 4, 5. However, in some cases, although plasma treatment effectively modifies the outermost rubber surface, migration of anti‐adherent moieties from the rubber formulation to the rubber/adhesive interface must be avoided, by strengthening this interface via crosslinking.…”

“…Due to their non‐polar nature, rubbers require a surface treatment which creates polar groups that make the rubber surface compatible with the polar polyurethane adhesive, usually used to bond these rubbers to different materials. Previous papers1–5 have shown the effectiveness of the radio frequency (RF) plasma treatment of different gases on styrene‐butadiene copolymers, which resides in ablation, removal of anti‐adherent moieties, and creation of polar CO and CO moieties on the rubber surface that increase the wettability of rubber by the adhesive. However, the effectiveness of the plasma treatment depends on the gas used to generate the plasma and also on the formulation of the rubber.…”

Influence of Rubber Formulation on Surface Modifications Produced by RF Plasma

“…As a result adhesion decreased [3,[20][21][22][23][24][25]. On the other hand, some studies in the literature dealing with the use of low pressure radiofrequency (RF) plasmas showed that the energetic environment of the plasma creates surface free radicals and also produces cleaning, ablation, crosslinking and chemical modifications on the rubber surface [1,[26][27][28][29][30][31][32][33][34][35][36][37].…”