| 초록 |
In this article, thermally expandable microcapsules (TEMs) were synthesized by high pressure suspension polymerization. The shell consists of acrylonitrile copolymer and the core consists of n-octane. 1,4-Butanediol dimethacrylate (BDDMA) was used as a crosslink agent and Halloysite nanotubes were used as a Pickering emulsifier. The contents of halloysite nanotubes affect not only the stability of the Pickering emulsions but also thermal properties of the microcapsules. Better expansion properties were obtained when crosslink agent was used. When halloysite contents were 0.25 wt. %, the most unstable Pickering emulsion was observed. After polymerization, when increasing the contents of halloysite nonotubes, contents of encapsulated hydrocarbon decreased. To figure out the expansion properties of microcapsules, the blowing properties of the TEMs were carried out in 180 ℃ convection oven. We found the largest expansion at 0.25 wt. %, and the smallest expansion at 3 wt. % of halloysite nanotubes. The morphology and the thermal stability of microcapsules were characterized by Thermogravimetric analysis (TGA) and Scanning Electron Microscope (SEM). |
