The modes of action of lubricants in elastomers and elastomer compounds
To modify the rheological behaviour of rubber compounds, in order to improve their processing behaviour, lubricants based on fatty acid derivatives are added at the mixing stage. This research has been directed towards identifying the modes of action of commercially available lubricants in a number of elastomers and elastomer compounds, with the objective of providing a rational basis for the further development of lubricants. The primary tool for rheological measurement was an advanced biconical rotor rheometer (Negretti TMS Rheometer); and a capillary rheometer was used to provide an independent verification of results. Conceptual and mathematical models have been proposed which provide a rational explanation and simulation of lubricant action. The conceptual model takes account of elastomer morphology, relative solubility parameters of elastomer and lubricant and chemical reactions between the lubricant and elastomer in order to explain internal lubrication, chain extension/crosslinking, solvation and external lubrication. The mathematical model simulates the primary lubricant actions of internal lubrication and chain extension/cross-linking.