Chemical Nature of the Rubber-To-Brass Bond

Abstract

In the initial stages of the reaction at the rubber-brass interface, formation of cuprous sulfide takes place. After this compound is formed, three possible reactions can occur. (1) The cuprous sulfide can unite with a “free” sulfur atom to form cupric sulfide. (2) The cuprous sulfide can attach itself to a sulfur atom already combined with the rubber. (3) The cuprous sulfide can attach itself directly to the rubber at points of unsaturation. In all cases of bad bonding brass examined by physical means, failure appeared to be due to nonuniformity in the structure of the plating. This lack of uniformity gave rise to a greater degree of corrosion and to conversion of the cuprous sulfide formed in the first place to cupric sulfide. Secondly, bad bonding stocks were characterized by two things : (1) The rate of reaction of the sulfur with rubber proceeded at a greater pace. (2) A greater degree of sulfide formation occurred at the brass rubber interface. This implied that reaction (2) was taking place, with the added complication of chains of sulfur atoms between rubber and copper. In other words it is necessary that a proper balance be maintained between the velocities of combination of sulfur with rubber and with brass. Thus, when the balance is disturbed, for example, by addition of more active accelerators, or, if the brass is in a more reactive state, then failure in adhesion results.

Powder and High-Solid Coatings as Anticorrosive Solutions for Marine and Offshore Applications? A Review

“…Adhesion can be described as the interatomic and intermolecular forces at the interface of two surfaces but in reality, it is very complex phenomenon implicating a multidisciplinary knowledge. Numerous studies have been performed on adhesion to describe it, to explain how it works and how it can be predicted as it is a key aspect in the protection offered by coating [38][39][40][41][42][43][44]. Several theories exist to explain adhesion but the aim of this paragraph is not to review them and detailed information can be found elsewhere [38][39][40][41][42][43][44].…”

Peel Test: A Tool to Assess The Stickiness of Honeydew Sugar

“…The electronic theory suggested by Deryaguin (1948) and Deryaguin (1957) and known as electrical double layer, electrostatic or parallel plate capacitor theory attributes adhesion to electrostatic phenomenon. Buchan (1946) suggested a theory based on chemical bonding. They assessed that adhesion is based on covalent chemical bonding appearing at the interface between two materials.…”

An overview of interphase’s formation and participation on water diffusion in epoxy/metal bonded assemblies

“…Firstly, the electrostatic attraction model proposed by Derjaguin and Smilga in 1967 [11] , this model considers a charge transfer when two materials of different natures are brought into contact. Secondly, the adhesion by chemical bonds proposed by Buchan in 1946 [12] . Sometimes it is possible to create covalent or ionic bonds at the interface between the adhesive and the substrate through chemical reactions.…”