Siloxane-polyhedral oligomeric silsesquioxane

PDMS nanocomposites with layered mica-type silicates were also reported.374 A two-step sol-gel process of the in situ precipitation of silica led to the development of siloxane-based nanocomposites with particularly high transparencies.3 5 Some unusual nanocomposites prepared by threading polymer chains through zeolites, mesoporous silica, or silica nanotubes were reviewed.3 6 Poly(4-vinylpyridine) nanocross-linked by octa(propylglycidyl ether) polyhedral oligomeric silsesquioxane was reported.377... 

Mantz, R.A., Jones, P.F., Chaffee, K.P., Lichtenhan, J.D., and Gilman, J.W., Thermolysis of polyhedral oligomeric silsesquioxane (POSS) micromers and POSS-siloxane copolymers, Chem Mater. 1996, 8, 1250. 

Pan, G. Mark, J. E. Schaefer, D. W., Synthesis and Characterization of Fillers of Controlled Structure Based on Polyhedral Oligomeric Silsesquioxane Cages, and Their Use in Reinforcing Siloxane Elastomers. J. Polym. Sei., Polym. Phys. Ed. 2003,41,3314-3323. 

Pan G, Mark JE, Schaefer DW (2003) Synthesis and characterization of fillers of controlled structure based on polyhedral oligomeric silsesquioxane cages and their use in reinforcing siloxane elastomers. J Polym Sci B Polym Phys 41(24) 3314—3323... 

The synthesis of polyhedral oligomeric silsesquioxane-siloxane copolymers has been achieved by Lichtenhan and coworkers. " " " Reaction of the hydroxyl groups on monomer 150 with iw-dimethylaminosilanes and siloxanes (151) resulted in the formation of polymers such as 152 using the methodology described in Scheme 36. " " This polymer had a glass transition at 23°C and a melting transition at 114°C. On the basis of GPC measurements, this polymer had a degree of polymerization of 21. 

Chapter 5 is a review of polyhedral oligomeric silsesquioxanes (POSS), hybrid POSS-organic copolymers, and POSS resin nanocomposites. Although silsesquioxanes have been known since tiie 1960s, only recently, through controlled synthesis and purification, have their structure and unique properties been determined and their useful applications been explored. This chapter is complemented by a discussion of the synthesis and properties of silica- and silsesquioxanes-containing polymer nanohybrids in Chapter 6. Chapter 7 involves a review of the preparation and characterization of siloxane-based polyviologens, polyurethanes, and divinylben-zene elastomers. 

Mantz RA, Jones PF, Chaffee KP, Lichtenhan JD, Gilman JW, Ismail IMK, Burmeister MJ (1996) Thermolysis of polyhedral oligomeric silsesquioxane (POSS) macromers and POSS-Siloxane copolymers. Chem Mater 8(6) 1250-1259. doi 10.1021/cm950536x... 

Spherical siloxanes (RSiOi 5), with polyhedral frameworks, also called silsesquioxanes, can be used as defined oligomeric models for surface-modified silica gels or polysiloxanes. Whereas silsesquioxanes with alkyl-, aryl-, hydrido-, and trimethylsiloxy groups are known for a long time [1], functionalized octa-[propyl-silsesquioxanes], [X-(CH2)3]g(SiOi.5)g, were synthesized for the first time in 1990 by Weidner, Zeller, Deubzer, and Frey [2]. Octa[(3-chloropropyl)-silsesquioxane], [Cl-(CH2)3]g(SiO, 5)g, could be obtained by hydrolysis of (3-chloropropyl)-trichlorosilane. 

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