Microcapsules with a silicone liquid core surrounded by a polymeric shell were synthesised through the controlled phase separation. The dispersed silicone phase consisted of the shell polymer PMMA, a good solvent for the PMMA (dichloromethane, DCM) and a poor solvent (methylhydrosiloxane dimethylsiloxane) for the PMMA. The morphology of the PMMA microcapsules was investigated by ATR‐FTIR and by optical microscopy. Microcapsules were prepared with different emulsifiers and different concentrations of acetone and PMMA in the oil phase. The thermal stability of the PMMA microcapsule and the content of the silicone oil core were assessed by TGA. 1H‐NMR spectroscopy and an extraction method were also used to determine the content of the silicone liquid core in the microcapsules.

The development of elastomer materials with a high dielectric permittivity has attracted increased interest over the last years due to their use in for example dielectric electroactive polymers. For this particular use, both the electrically insulating properties -as well as the mechanical properties of the elastomer -have to be tightly controlled in order not to destroy favorable elastic properties by the addition of particles. In the following, expanded graphite in low concentrations (up to 5 wt%) are investigated as a possible candidate as filler materials in very soft elastomers, which by the addition of traditional fillers in the necessary amounts would either lose their stability or their softness. Furthermore the influence of several mixing procedures on the electrical and mechanical properties is investigated.

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Gamma irradiation was investigated as a triggering stimulus for the activation of poly(methyl methacrylate) (PMMA) microcapsules. PMMA was exposed to varying doses of irradiation and analyzed by differential scanning calorimetry, size‐exclusion chromatography, and nuclear magnetic resonance. It was found that the glass transition temperature (Tg) of the polymer decreases at low irradiation doses. Additionally, Tg can be physically adjusted by adding a plasticizer, and both kinds of microcapsules were successfully prepared with non‐plasticized and plasticized PMMA shell. Finally, impermeable microcapsules were shown to become permeable after irradiation and release an encapsulated cross‐linker, which enables the remotely controlled formation of polydimethylsiloxanes in traditionally unavailable places. Therefore, the activation method has significant implications for industrial application. Copyright © 2015 John Wiley & Sons, Ltd.

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