Polyhedral oligomeric silsesquioxane molecules

Recently, ROMP of silicon-containing norbornenes was used for creation of inorganic-organic hybrid materials. Particularly, incorporation of the polyhedral oligomeric silsesquioxanes molecule (POSS) in norbornene and its ROMP copolymerization with norbornene or norbornene-dicarboxylic acid gave POSS-containing copolymers [208, 209],... 

Polyhedral oligomeric silsesquioxanes (POSS) are known molecules having various structures [1] as seen in Fig. 1. However double-decker shaped silsesquioxane has not been obtained. POSS is an interesting class of monomers for the preparation of silicon-based polymers. In recent years, silsesquioxane-based polymers have received much attention because of their useful properties, which include heat resistance, mechanical stability, low dielectric constant, etc. [2, 3],... 

Polyhedral oligomeric silsesquioxane (POSS) has been described as a three-dimensional "cage-shaped molecule composed of a silicon-oxygen framework bonded to organic groups that make it compatible with a polymer matrix. Unlike conventional nanofillers that must be dispersed and exfoliated to be useful, POSS molecules formulated in the resin are induced by shear to "self-assemble ... 

ATRP from Silsesquioxane Initiators. In addition to silsesquioxanes with vinyl based monomeric units attached to corner silicon atoms, other species can be bonded to the cubes. One such example is the silsesquioxane shown in Scheme 7. Termed benzyl chloride functionalized polyhedral oligomeric silsesquioxane (benzyl chloride-POSS), the molecule contains seven cyclopentyl groups, which provide increased solubility in organic solvents, and one benzyl chloride moiety which can serve as an initiator for ATRP. Studies of such initiators may be of interest due to the bulky nature of the initiating species. Furthermore, the high temperature stability of the inorganic cubes may lend some interesting thermal properties to polymers initiated from it. 

Another strategy for moisture-adaptive shape-memory polymer preparation is to use water soluble segments as a soft segment to prepare SMPUs. Preparation is by polyhedral oligomeric silsesquioxane (POSS) molecules and poly(ethylene glycol) that act as the hydrophobic and hydrophilic groups. The POSS groups... 

Grubb D and Bala V (1999) Simultaneous SAXS, WAXS and local strain measurement deformation of row-structure in LLDPE, Polym Mater Sci Eng 81 357-358. Fu B X, Hsiao B S, Pagola S, Stephens P, White H, Rafailovich M, Sokolov J, Mather P T, Jeon H G, Phillips S, Lichtenhan J and Schwab J (2000) Structural development during deformation of polyurethane containing polyhedral oligomeric silsesquioxanes (POSS) molecules. Polymer 42 599-611. 

Polyhedral oligomeric silsesquioxanes (POSS) represent an important class of nanostructured materials that can be successfully used in the design of novel composite systems [1], The typical structure of POSS molecule consists of a cubic cage where the central inorganic core is functionalized with organic entities [2], The interest in POSS application for the design of polymer nanocomposites is particularly due to the fact that the organic substituents can be tailored to facilitate incorporation of the POSS molecules into the polymer martix. 

The paper describes the effect of polyhedral oligomeric silsesquioxanes (POSS) on the properties of HNBR composite materials. The results indicate that inclusion of the POSS molecules into the elastomer matrix imparts lower reinforcing effect in comparison with nanoscale silica. 

Bruce X, Fu MYG, Hsiao BS, Phillips S, Viers B, Blanski R, Ruth P (2003) Physical gelation in ethylene - propylene copolymer melts induced by polyhedral oligomeric silsesquioxane (POSS) molecules. Polymer 44(5) 1499-1506... 

Rotello et al. used a similar system, relying mainly on multiple thymine/2,6-diamino-pyridine interactions (Fig. 72). Small molecules (such as flavines [241], ferrocenes [242]) can be boimd via a single, thymine/2,6-di-aminopyridine interaction. This can lead to materials with reversible properties, where the redox activity of the surface-bound functional moiety can interact with a current form of the (Au-) surface. The concept has been extended to nanoparticles (Au-NP) [243] and polyhedral ohgomeric silsesquioxanes [244]. The presence of the oligomeric silsesquioxanes was proven by XPS measurements, detecting the Si(2p) peak on the surface after deposition. 

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