School of Engineering and Materials Science
Research Student Roll of Honours
PhD Thesis: Carbon Black Filler Reinforcement of Elastomers
Author: JHA, Vineetkumar
Supervisor(s): James Busfield
Fillers enhance the properties of an elastomer by improving its mechanical properties such as the abrasion resistance or the fatigue life. In order to design a product and understand the properties of the filled elastomers used in industry; it is important to understand the effect of a filler on the composite elastomer. Strain amplification, a bound rubber layer, molecular slippage, hydrodynamic effects, occluded rubber and various other models have been previously used to describe filled rubber reinforcement and these various filler-rubber interactions. Different approaches such as finite element micro-structural modelling, molecular modelling, mathematical modelling, TEM and SEM imaging, tomography as well as measurements of the changes in electrical and mechanical properties with strain can be used to examine these various theories of filler reinforcement more closely.
Here, the finite element micro-structural analysis approach has been used to predict how the mechanical properties of elastomers changes with strain. The selection of appropriate boundary conditions and the correct stored energy function for the rubber phase are seen to be very important. To understand the filler network and the filler-rubber interactions more closely the electrical and mechanical behaviour of the filled elastomer under strain for various different conditions have also been measured. One particularly promising outcome is the discovery that for the filler, Printex-XE2, there is a fully reversible change in electrical resistivity with strain. This suggests that elastomer composites containing this filler may have practical applications as a strain sensor or a pressure sensor device.
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