کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
7889022 | 1509797 | 2018 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Generation of meso- and microporous structures by pyrolysis of polysiloxane microspheres and by HF etching of SiOC microspheres
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موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
سرامیک و کامپوزیت
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Generation of meso- and microporous structures by pyrolysis of polysiloxane microspheres and by HF etching of SiOC microspheres Generation of meso- and microporous structures by pyrolysis of polysiloxane microspheres and by HF etching of SiOC microspheres](/preview/png/7889022.png)
چکیده انگلیسی
The porosity of polysiloxane microspheres obtained by emulsion processing of variably modified polyhydromethylsiloxane (PHMS) and subjected to pyrolysis in an Ar atmosphere at 450-650 °C was studied. Materials having micro- and mesopores with specific surface areas (SSAs) of up to 786 m2/g and pore volumes of up to 0.35 cm3/g were obtained. A high porosity was displayed by the microspheres heated at 600 °C that underwent deep depolymerization processes. Some polysiloxane microspheres were ceramized at temperatures of 1200-1500 °C and were subjected to etching by 35% aqueous HF. The microspheres heated to 1200-1400 °C were free of microcracks, whereas those ceramized at 1500 °C showed microcracks and macropores, although they preserved their spherical structure well. All of the microspheres ceramized at temperatures of 1200-1400 °C had low porosity. HF etching granted high micro- and mesoporosity to the materials ceramized at 1300-1500 °C. Microspheres heated at 1500 °C showed specific surface areas above 1000 m2/g after etching. These microspheres had low oxygen contents and were mostly composed of silicon carbide. Since they also showed macroporosity, HF etching of the polysiloxane microspheres ceramized at 1500 °C could be used to obtain hierarchically mesoporous-macroporous ceramic microspheres.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Ceramics International - Volume 44, Issue 1, January 2018, Pages 374-383
Journal: Ceramics International - Volume 44, Issue 1, January 2018, Pages 374-383
نویسندگان
Witold Fortuniak, Piotr Pospiech, Urszula Mizerska, Julian Chojnowski, Stanislaw Slomkowski, Anna Nyczyk-Malinowska, Agnieszka Wojteczko, Ewa Wisla-Walsh, Magdalena Hasik,