title: Preceramic polysiloxane networks obtained by hydrosilylation of 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane.
abstract: Precreamic polysiloxane networks were prepared by hydrosilylation of 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane (D(4)(Vi)) with a series of linear hydrogensiloxanes as well as with a cyclic hydrogensiloxane, namely 2,4,6,8-tetramethylcyclotetrasiloxane (D(4)(H)) at various hydrogensiloxane/D(4)(Vi) molar ratios in the starting reaction mixture. FTIR spectroscopic measurements conducted during the processes as well as for the reaction products allowed to reveal that the rate of D(4)(Vi) hydrosilylation as well as its efficiency are influenced by the type of hydrogensiloxane used and by the reactants molar ratio. Ceramic yields determined at 1000°C by thermogravimetric analyses were higher for D(4)(Vi)-D(4)(H) than for D(4)(Vi) - linear hydrogensiloxane networks (86-89% vs 65-76%, respectively). Preceramic polysiloxanes prepared as well as the products of their pyrolysis obtained after thermal investigations were monolithic, pore-less materials.
authors.affiliation: Faculty of Materials Science and Ceramics, AGH-University of Science and Technology, Al. Mickiewicza 30, 30-059 Kraków, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Nyczyk
authors.forename: Czesława
authors.initials: C
authors.lastname: Paluszkiewicz
authors.forename: Anna
authors.initials: A
authors.lastname: Pyda
authors.forename: Magdalena
authors.initials: M
authors.lastname: Hasik
mesh_terms: D002516:Ceramics / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D012833:Siloxanes / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D013818:Thermogravimetry; D014732:Vibration; D014867:Water / Q000737:chemistry*
chemical_list: D012833:Siloxanes; D014867:Water; C507689:1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane