Influence of Filler Type

In the case of SBR, which cannot easily achieve bond formation, when 40 phr of easy processing channel (EPC) black is added the tack is reduced and then remains almost the same during mastication. The filler in this case further restricts chain mobility, reducing interfacial interactions and thus leading to lower tack. If an SBR can be synthesised with 

The autohesion of rubber compounds is found to marginally decrease with increasing amounts of plasticiser/processing oils such as aromatic, naphthenic or paraffinic [5]. Since plasticiser/processing oil improves the chain mobility of the rubbers this behaviour shows that interdiffusion alone cannot explain all the factors associated with tack or autohesion. But if the modulus is maintained at a constant by the addition of carbon black, oil essentially has no effect on adhesion [9]. 

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Several studies have considered the influence of filler type, size, concentration and geometry on shear yielding in highly loaded polymer melts. For example, the dynamic viscosity of polyethylene containing glass spheres, barium sulfate and calcium carbonate of various particle sizes was reported by Kambe and Takano [46]. Viscosity at very low frequencies was found to be sensitive to the network structure formed by the particles, and increased with filler concentration and decreasing particle size. However, the effects observed were dependent on the nature of the filler and its interaction with the polymer melt. 

Rheological data can provide useful information about the influence of filler type, content and surface treatment on the overall melt viscosity of polymer containing particulate additive. Many reports exist describing these effects [44-46]. 

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