Rubber rolling on rough surfaces

Abstract

Earlier studies suggested that the adhesion of rubber to a substrate is increased by slight surface roughening. Rolling resistance experiments confirm this effect for very soft vulcanisates and unvulcanised rubber. Elastic analyses are shown not to predict the increased adhesion. The important factors suggested as giving rise to the increase for vulcanisates are stress relaxation during the contact period and loss at final detachment of the elastic energy built up in 'islands' of contact during separation. For the unvulcanised rubbers flow is shown to be the major factor. It leads to a high degree of intimate contact with rough surfaces, and also to energy dissipation around regions of locally higher adhesion where yielding occurs during peeling.