Rupture of rubber. IV. Tear properties of vulcanizates containing carbon black

Abstract A method of studying tear behavior has been described in a previous paper (Part III, subsequently referred to as III), and was illustrated by results obtained with natural rubber and GR-S gum vulcanizates, i.e., vulcanizates containing no added ingredients apart from those necessary for vulcanization. In the present paper the method is applied to vulcanizates containing different types of carbon black. Vulcanizates of this type are of considerable interest, since the carbon black can appreciably modify physical properties such as stiffness and tensile strength and can induce pronounced anisotropy in tearing, referred to by Buist as knotty tearing.