A Sputtering Deposition of Al Enhances the Output Reproducibility in a Conducting Rubber Force Sensor

Compressive force sensors or pressure sensors are indispensable to tactile sensors in humanoid robots. It is investigated that low-cost electro-conducting rubber sheets are applied to the force sensor, of which the biggest problem is its poor reproducibility. It was found that the aluminum deposition by a vacuum evaporation method shows excellent characteristics but suffers deterioration by a radiation heating effect. The aluminum electrode was deposited by a sputtering method, known to have an advantage of a low-temperature method, and the reproducibility of the output was improved.

Modified graphite filled natural rubber composites with good thermal conductivity

The rubber composites with good thermal conductivity contribute to heat dissipation of tires. Graphite filled natural rubber composites were developed in this study to provide good thermal conductivity. Graphite was coated with polyacrylate polymerized by monomers including methyl methacrylate, n-butyl acrylate and acrylic acid. The ratios between a filler and acrylate polymerization emulsion and those between monomers were varied. Eight types of surface modification formulas were experimentally investigated. Modification formula can affect coating results and composite properties greatly. The best coating type was achieved by a ratio of1:1 between methyl methacrylate and n-butyl acrylate. The coating of graphite was thermally stable in a running tire. Filled with modified graphite, the tire thermal conductivity reached up to 0.517–0.569 W·m-1·K-1. In addition, the mechanical performance was improved with increased crosslink density, extended scorch time and short vulcanization time.

Piezoresistive Characteristic of Conductive Rubber for Flexible Tactile Sensor

In the research of 2D flexible tactile sensor matrix,pressure-sensitive conductive rubber was developed and tested in which carbon black was used as its conductive phase and silicon rubber as its matrix layer.Experiments were undertaken and the resultant data were used for its piezoresistive characteristics investigation for two kinds of electrode connection configurations,the surface directive connection and embedded connection.It is found that due to the rather strong nonlinearity of the piezoresistive characteristic curves obtained,a higher correlation relationship can be obtained by means of quadratic polynomial fitting.It also showed that the embedded electrode assembling has higher fitting accuracy while the surface directive connection has better mechanical sensitivity.

Preparation and Properties of Conductive Foamed Silicone Rubber

The conductive foamed silicone rubber was prepared by Polymethylvinylsiloxane(PMVS)mixed with acetylene black,fumed silica,and AC foaming agent(azodicarbonamide).Influences of fillers on the microstructure,electrical conductivity and mechanical property were discussed.The results showed that the pore structure was affected by acetylene black.Acetylene black delayed the vulcanization speed of silicone rubbers,leading to bigger pores.Higher content of acetylene black decreased the mechanical properties and the electrical resistivity of rubbers.Fumed silica increased the mechanical properties and limited the aggregation of gas.Higher content of fumed silica led to small and obturator pores generated.Higher content of fumed silica increase the mechanical properties and the electrical resistivity of rubbers.AC foaming agents generated more gas,leading to bigger and irregular pores which affected the mechanical properties negatively,meanwhile AC foaming agents increased the conductivity of rubbers.