Naslov
Softening of octyl-modified phenylsilsesquioxanes

Autori
Macan, Jelena ; Tadanaga, Kiyoharu ; Tatsumisago, Masahiro

Izvornik
Polimeri : časopis za plastiku i gumu (0351-1871) 32 (2011), 3-4; 112-118

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
organic-inorganic hybrid material ; polysilsesquioxanes ; sol-gel process ; thermal properties

Sažetak
Octyl-modifi ed phenylsilsesquioxanes were prepared from phenyltriethoxysilane and octyltriethoxysilane by two-step acid-base catalysed sol-gel process. Resulting silsesquioxanes were characterized by scanning electron microscopy, X-ray diffraction analysis, gel permeation chromatography and Fourier-transform infrared spectroscopy, while the thermal properties were investigated by differential scanning calorimetry and thermogravimetric analysis. Morphology of polysilsesquioxanes was found to greatly depend on ratio of alkoxides, presumably because of poor miscibility of long alkyl chains which results in a less homogeneous initial mixture. Long alkyl chains also present steric hindrance to condensation of phenyltriethoxysilane eventually preventing the formation of particles. Incomplete condensation caused the decrease of softening temperature from 160°C to ~50°C and overall poorer thermal stability of polysilsesquioxanes. Decrease in initial temperature of degradation by at least 150°C is probably caused by alkyl chains exposed on the surface of the particles. Increased solvent content improves incorporation of octyl chains due to better solubility and yields polysilsesquioxanes with a more regular structure and a more homogeneous particle size distribution. On the other hand it adversely influences the level of condensation and the softening temperature.

Izvorni jezik
Engleski

Znanstvena područja
Kemijsko inženjerstvo, Temeljne tehničke znanosti

POVEZANOST RADA