Silicone-containing polymers stability

SiC is an excellent nonoxide ceramic with high-temperature stability and suitable mechanical properties. Since silicon-containing polymers are generally used for preparing nonoxide ceramics, various polymeric precursors with different structures have been designed. Preceramic polycarbosilane (PCS), used for preparing commercial Nicalon fiber,... 

In order to improve the solubility of aromatic polymers silicon-containing polymers have also been synthesized, by introduction of siloxane or silarylene linkages into polymer backbones such as polyamides, polybenzimidazoles and polyimides [50]. The resultant polymers show fair solubility in organic solvents but most of them have poorer thermal stability then their analogues without siloxane or silarylene linkages. 

The use of Diels-Alder and platinum-catalyzed polyaddition reactions of divinyl ferrocene derivatives to prepare ferrocene-containing polycarbosUanes has also been described [32, 34, 35]. These reactions were also used to prepare materials with additional functional groups that led to ferrocene- and silicon-containing polyesters, polyamides, and polyurethanes. Molecular weights varied in the range 3800-6000 and products were liquids or elastomers. The authors only carried out comparative studies of the thermal stabilities of these polymers. 

A new convenient polymer modification for synthesis of silanol-containing polymer was developed by the selective oxidation of the Si—H bond with a dimethyldioxirane solution in acetone. The oxyfunctionalization of the silane precursor polymers can be utilized to synthesize a wide variety of silanol-containing polymers. Control over the properties of these silanol polymers, such as stability and self-association of silanols, was realized through the placement of different substitute groups bonded directly to the silicon atom. The miscibility in either polymer blends or polymeric hybrids was achieved by the formation of strong inter-polymer hydrogen bonds between the... 

DPPES was grafted onto the surface of GNO by condensation to form a synergistic phosphorus/silicon-containing GNO flame retardant (DPPES-GNO). A series of nanocomposites that contained 0,1,5, and 10 wt% DPPES-GNO was prepared. XPS, FTIR, Raman spectroscopy, and TEM verified that DPPES covalently bonded to GNO. Furthermore, the addition of DPPES-GNO (up to 10 wt%) to neat epoxy significantly increased its thermal stability and improved the char yield and LOI by 42% and 80%, respectively. The phosphorus, silicon, and GNO layer stmctures of DPPES-GNO caused the continuous and insulating char layer to protect the inner polymer matrix. The approach that is described herein has great potential for the development of a novel synergistic phosphorus/silicon—GNO flame retardant with polymer nanocomposite applications. 

Chavez, R., lonescu, E., Easel, C., Riedel, R. (2010). Silicon-containing polyimide-based polymers with high temperature stability. Chemistry of Materials, 22(13), 3823-3825. doi 10.1021/cml010746. 

Tiptipakorn, S. Damrongsakkul, S. Ando, S. Hemvichian, K. and Rimdnsit, S., Thermal degradation behaviors of polybenzoxazine and silicon-containing polyimide blends, Polym. Degrad. StabiL, 91(7), 1265-1278 (2007). 

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