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Facile preparation of ultralight polymer‐derived Si OCN ceramic aerogels with hierarchical pore structure
Author(s) -
Zhao Wanyu,
Shao Gang,
Han Shixian,
Cai Chunhui,
Liu Xingcen,
Sun Mengran,
Wang Hailong,
Li Xinjian,
Zhang Rui,
An Linan
Publication year - 2019
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.16100
Subject(s) - materials science , ceramic , chemical engineering , polymer , divinylbenzene , aerogel , thermogravimetric analysis , porosity , cyclohexane , phase (matter) , composite material , organic chemistry , copolymer , chemistry , styrene , engineering
Abstract Si OCN ceramic aerogels with lightweight, high surface areas, and macro‐meso pores have been synthesized by a facile method combining freeze‐drying technique and polymer‐derived ceramic route. The wet gels are synthesized via the hydrosilylation reaction between polysilazane and divinylbenzene with cyclohexane as solvent. The solvent is then removed by a freeze‐drying process to form pre‐ceramic aerogels. The Si OCN ceramic aerogels are finally obtained by pyrolyzing the pre‐ceramic aerogels at 1000°C in ultrahigh purity N 2 . The thermogravimetric and mass spectrometry system ( TG / DSC ‐ MS ) is used to investigate the polymer‐to‐ceramic conversion process during pyrolysis. The phase composition, structure, and morphology of the Si OCN ceramic aerogels are investigated by XRD , FT‐IR , XPS , and SEM . The results show that Si OCN ceramic aerogels are composed of amorphous matrix phase and “free carbon” phase. The Si OCN aerogels possess three‐dimensional (3D) network porous structure with low density (0.19 g/cm 3 ), high specific surface area (134 m 2 /g), large pore volume (0.49 cm 3 /g), and hierarchical pore structures of both macro and meso pores. The formation mechanism and evolution process of Si OCN ceramic aerogels are discussed.