Browsing by Author "Jones, AS"

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    Synthesis of nanoporous silicon carbide via the preceramic polymer route
    (Elsevier, 2009-02-15) Maddocks, AR; Cassidy, DJ; Jones, AS; Harris, AT
    Nanoporous silicon carbide materials were prepared by the pyrolysis of the preceramic polymer, polycarbosilane (PCS), with and without the addition of an inert filler (nano- and micron-sized silicon carbide powders). Hydrosilylation crosslinking of PCS with divinylbenzene prior to pyrolysis appeared to have little influence on the development of micro- and mesoporosity. Maximum micropore volumes were 0.28 cm3 g−1 for non-crosslinked PCS and 0.25, 0.33 and 0.32 cm3 g−1 for PCS crosslinked with 2, 6 and 10 wt.% DVB respectively. Micropore volumes decreased under hydrothermal conditions to 0.03 cm3 g−1 for non-crosslinked and 0 cm3 g−1 for crosslinked PCS. Porosity was also lost at temperatures above 700°C. The addition of nano-sized SiC powders to PCS prior to pyrolysis maintained mesoporosity to temperatures of 1200°C, however, micron-sized SiC powders did not maintain porosity above 800°C. The modal pore size in pellets formed by compressing micron-sized powders with the preceramic polymer was 5 μm compared to 30 nm when nano-sized powders were used. © 2009, Elsevier Ltd.