A report on this meeting was published in materials world. Click here to read the article

Presentations from the Rubber in Engineering Group ATDM. 

The presentations (originally MS Powerpoint presentations) are available here in PDF format. Please click on the title to download.

This content is accessible to IOM3 members only

Liquid crystal elastomers: what are their applications? (PDF 2MB)

James Adams (University of Surrey)

Liquid crystalline molecules can be incorporated into a soft polymeric materials providing a novel coupling between the microscopic orientational order of the liquid crystals and the mechanical strain of the solid. The wide range of phases of liquid crystals offers a rich variety of material properties, including highly anisotropic mechanical response and the formation of microstructure on deformation. I will present a general overview of liquid crystalline elastomers, including smectic elastomers, and some more recent experimental developments of photoactuated devices.

Quantum Tunnelling Composite (PDF 1.7MB)

Adam Graham (Peratech Ltd)

Quantum Tunnelling Composite (QTC) is a metal polymer composite, commercialised and produced using a patented manufacture process. This process ensures that the metal particles within an elastomeric polymer matrix maintain a highly fractal surface morphology where nano-scale point features are retained on the particles and are coated in polymer. This structure provides unique electronic behaviour showing a resistance in excess of 100 MΩ at rest, for a material loaded above the expected percolation threshold and an exponential increase in conductivity under all types of mechanical deformation. Increase in sample compression leads to a lower electrical resistance through the material. Current-voltage characteristics show a hysteresis effect due to current storage in the QTC material as a current is passed. The hysteresis is shown to be reduced as the applied compression on the material is increased until an Ohmic regime is reached at very high compressions, above 70% linear compression. At these high compressions Joule heating is also proven to occur as a result of the power dissipated in the sample by I-V cycling. The Joule heating is sufficient to influence the physical characteristics of the sample and expand it, creating a current limiting device.

Conductive polymer blends (PDF 1.6MB)

Peter Foot (Kingston University)

This paper considers how blending a conductive polymer with a conventional rubber material will create a conductive polymer with potential for strain sensing or other smart applications. 

Strain sensitive filled elastomers (PDF 2.2MB)

Martyn Bennett (Artis), Alan Thomas, Vineet Jha and James Busfield (QMUL)

The most common reinforcing filler used in the rubber industry is an electrically conductive carbon black and the inclusion of such fillers reduces the resistivity of the elastomer compound. Previous work has shown that for elastomers containing carbon black fillers at a volume fraction above the percolation threshold the resistivity changes with strain, the precise resistivity versus strain behaviour being non linear and irreversible for conventional carbon black fillers. A strain measuring device, deriving strain directly from a measure of the resistivity, requires that the behaviour be reversible and reproducible from cycle to cycle. This work presents the electrical resistivity behaviour of a natural rubber (NR) compound filled with Printex XE2 carbon black. For the first time reversible electrical resistivity dependence with strain is reported for an elastomer filled with Printex XE2. This reversible behaviour under strain opens up the possibility of applications such as a flexible load sensor, pressure sensor or switch.