Factors Affecting Adhesion of Rubbers

The adhesion of rubbers is further complicated by the rheology of rubber and its added compounding constituents. Blending two or more rubbers will give more complexity to the flow and adhesion behaviour of the system. The ability of the rubber compound to flow and establish intimate contact with the substrate is of paramount importance, to enable the forces discussed previously to establish the conditions required for optimal adhesion. Any material which interferes with the establishment of the interface must be avoided. The establishment of a stable, strong interface between the two materials is the foremost requirement for successful adhesion. 

The processes which are likely to determine the interface formation are  

The ability of the rubber to flow must be a priority in the compound design. Without the ability to flow readily the rubber compound will not be capable of wetting out the surface of the adhesive film and thus the necessary interfacial contact will not be completely achieved. Reduction of the molecular weight of the rubber is beneficial, but other means of promoting flow may be problematical, i.e., addition of oils and plasticisers. Oils, plasticisers and waxy materials will almost certainly exude to the rubber surface either immediately after compound preparation or during the establishment of the interface. Similarly some plasticisers are known to travel to and into the interface layers with time, breaking down the adhesion and resulting in complete failure of the bond. 

Complete wetting of the adherend surface is essential if the best interfacial bond strength is to be achieved. However, because of incomplete wetting not all of the surface transforms 

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Other Factors Affecting Adhesion of Rubber to Brass Coated Steel Wire... 

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