Silsesquioxanes multifunctional

The first step for the core-first stars is the synthesis of multifunctional initiators. Since it is difficult to prepare initiators that tolerate the conditions of ionic polymerization, mostly the initiators are designed for controlled radical polymerization. Calixarenes [39, 58-61], sugars (glucose, saccharose, or cyclodextrins) [62-68], and silsesquioxane NPs [28, 69] have been employed as cores for various star polymers. For the growth of the arms, mostly controlled radical polymerizations were used. There are only very rare cases of stars made from nitroxide-mediated radical polymerization (NMRP) [70] or reversible addition-fragmentation chain transfer (RAFT) techniques [71,72], In the RAFT technique one has to differentiate between approaches where the chain transfer agent is attached by its R- or Z-function. ATRP is the most frequently used technique to build various star polymers [27, 28],... 

Compositematerialcontainingatleastonephasewithconstituentsofl-lOOmn in size can be termed nanocomposites. Nanoparticles commonly used in the nanocomposite include single-walled carbon nanotube (SWCNT), double-walled carbon nanotube (DWCNT), multi-walled carbon nanotubes (MWCNT), carbon nanofiber (CNF), graphite nanoplatelet (GNP), mont-morillonite (MMT), nanoclay and polyhedral oligomeric silsesquioxanes (POSS). Other nanoparticles, such as SiOj, AljOj, TiOj and nanosilica are also used in the nanocomposite. The potential benefits of the nanoparticles for structural and multifunctional nanocomposites are sunamarized below. 

Polyhedral oligomeric silsesquioxanes (POSSs) could be used as building blocks for multifunctional composite solids and for hierarchical inorganic/organic hybrid architectures. These compounds may include inert hydrocarbon moieties, reactive groups, and... 

The present work focuses on the synthesis of novel multifunctional epoxy and vinyl ether monomers bearing the Tg silsesquioxane core and a study of their behaviour under photoinitiated cationic polymerization conditions. 

Bian, Y., Pejanovic, S., Kenny, J., Mijovic, J. Dynamics of multifunctional polyhedral oligomeric silsesquioxane/poly(propylene oxide) nanocomposites as studied by dielectric relaxation spectroscopy and d5mamic mechanical spectroscopy. Macromolecules 40 (2007) Boucher, V.M., Cangialosi, D., Alegria, A., Colmenero, J. Time dependence of the segmental relaxation time of poly(vinyl acetate)-silica nanocomposites. Phys. Rev. E 86, 041501 (2012)... 

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