Highly Efficient Rubber-to-Stainless Steel Bonding by Nanometer-Thin Cross-linked Polymer Brushes

Abstract

Stainless steel (SS) surfaces were grafted with poly(glycidyl methacrylate) (PGMA) brushes that were post-modified using allylamine, diallylamine, and propylamine as reagents. Likewise, poly[2-(diethylamino)ethyl methacrylate] brushes were synthesized. All samples were compression molded with uncured ethylene-propylene-diene M-class rubber and dicumyl peroxide and vulcanized for 12 min at 170 °C. The efficiency of the novel bonding solution was evaluated through peel experiments. Two parameters, the fracture toughness ( ) and the cohesive-to-adhesive fracture ratio ( A r ), were calculated to evaluate the strength and the performance of the coupling, respectively. For the nanometer-thin PGMA films modified with allylamine, in particular, full cohesive fracture was obtained. The obtained values of (15.4 ± 1.1 N mm –1 ) and A r (1.00 ± 0.01) matched those obtained for a micrometer-thick commercial bonding agent. Cross-linking of polymer brushes by intermolecular reactions by the primary amines proved to have a significant impact on the type of fracture (cohesive/adhesive) and the performance of the adhesives.

Facile Access to Disulfide/Thiol Containing Poly(glycidyl methacrylate) Brushes as Potential Rubber Adhesive Layers

“…The method of surface-initiated activators regenerated by electron transfer atom transfer radical polymerization (SI-ARGET-ATRP) is described elsewhere. 11 In short, SS Br substrates were immersed in an argon purged solution of 1:1 (v/v) MeOH/ Milli-Q water (9 mL in total) with GMA (1 mL, 0.8 M), BiPy (12.4 mg, 8.0 mM), NaAsc (7 mg, 3.5 mM), and CuCl 2 •2H 2 O (6.8 mg, 4.0 mM) at 0 °C for 0.5 h. The substrates were rinsed in Milli-Q water The solution gradually became deep dark red due to the continuously increasing polysulfide chain length. 26 2.5.…”

“…Ellipsometry, Infrared Reflection Absorption Spectroscopy (IRRAS), and X-ray Photoelectron Spectroscopy (XPS). Experimental procedures for ellipsometry, XPS (relative sensitivity factors are stated in Table S2), and IRRAS were adopted from Buhl et al 11 Thermal experiments conducted with IRRAS were performed in a custom-built furnace installed in the experiment module, which was thoroughly flushed (1 h) with dry atmospheric air (dewpoint < −60 °C). 29 The temperature was PID regulated using an internal K type thermocouple (±3 °C).…”

“…Compression molding was employed to cure the rubber and facilitate covalent cross-linking between rubber and SS PGMA , SS Sulfide , SS Thiol , and SS Chemosil samples. The procedure is adopted from Buhl et al [see Figure S2 (items 1–8) for mold design and procedure] …”

“…One of the most widely used polymers for postpolymerization modification is poly­(glycidyl methacrylate) (PGMA) containing epoxide units that readily undergo ring-opening reaction by nucleophilic attack. The most common nucleophiles used to functionalize PGMA brushes include amines, − azides, , and thiols. − Using disulfides as cross-linking agents represents an attractive option, since the linkages in this case, i.e., S–S bonds, are responsive in that they may be broken on demand. A study by Guo et al showed how postpolymerization with cystamine induced a wrinkled morphology by controlling the degree of modification of a styrene/maleic anhydride copolymer.…”

Polymer Brush Coating and Adhesion Technology at Scale

“…While alkenes may serve as such handles and react with EPDM during the vulcanization process, alkene-functionalized monomers are not readily compatible with a radical polymerization, and hence such polymer brushes cannot be directly synthesized. In a study by Buhl et al, double bonds were introduced to PGMA brushes on SS in a post-polymerization modification by reaction with allylamine or diallylamine ( Table 1 ) [ 50 ]. The immobilized alkene groups facilitated the reaction between the polymer brushes and EPDM rubber during the overmolding and vulcanization process (170 °C for 12 min) and provided strong adhesion between the SS substrates and EPDM.…”