【摘 要】
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Solid silicon oxycarbide(SiCO)ceramic microspheres and rigid porous siloxane microspheres were obtained in a two step process.First,polysiloxane microsphere
【机 构】
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Center of Molecular and Macromolecular Studies,Polish Academy of Sciences,112 Sienkiewicza,90-363 Lo
论文部分内容阅读
Solid silicon oxycarbide(SiCO)ceramic microspheres and rigid porous siloxane microspheres were obtained in a two step process.First,polysiloxane microspheres with a large number of Si-OH groups in their bulk and on their surface were synthesized from polyhydromethylsiloxane(PHMS)using a recently developed process.The process included a combination of three reactions of Si-H groups of PHMS occurring in aqueous emulsion and catalyzed by the same Karstedt Pt(0)complex:(i)hydrosilylation of 1,3-divinyltetramethyldisiloxane(DVTMDS),(ii)hydrolysis,(iii)dehydrogenocondensation involving the SiOH groups formed during the hydrolysis.DVTMDS was grafted on PHMS prior to emulsification.Microspheres had a loose structure and were able to absorb a significant amount of organic solvents.In the second step the microspheres were subjected to pyrolysis with heating in the argon atmosphere at following temperatures: 400,700 and 1000 ℃.These heated at 400 ℃ had micro and mezopores,while those heated at 700 and 1000 ℃ gave spherical solid SiCO ceramic particles.Polysiloxane microspheres and microspheres obtained by pyrolysis of the former were analyzed by 29Si and 13C MAS NMR,FTIR,SEM,and N2 gas adsorption.
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