Polysilsesquioxane

Bridged polysilsesquioxanes having covalently bound acidic groups, introduced via modification of the disulfide linkages within the network, were studied as solid-state electrolytes for proton-exchange fuel cell applications.473 Also, short-chain polysiloxanes with oligoethylene glycol side chains, doped with lithium salts, were studied as polymer electrolytes for lithium batteries. 

Baney, R. H. Cao, X. Polysilsesquioxanes. In Silicon-Containing Polymer. The Science and Technology of Their Synthesis and Applications-, Jones, R. G., Ando, W., Chojnowski, J., Eds. Kluwer Dordrecht, 2000 Chapter 6, pp 157-184. 

Pyun, J. Xia, J. Matyjaszewski, K. Organic-Inorganic Hybrid Materials from Polysiloxanes and Polysilsesquioxanes Using Controlled/ Living Radical Polymerization. In Synthesis and Properties of Silicones and Silicone-Modified Materials Clarson, S. J., Fitzgerald, J. J., Owen, M. J., Smith, S. D., Van Dyke, M. E., Eds. ACS Symposium Series 838 American Chemical Society Washington, DC, 2003 pp 273—284. 

Polysilsesquioxane xerogels Sol-gel processed TiOj, doped by organic compounds having non-linear optical properties CdS TiOj... 

A. Pressure Sensitive Adhesives a. Polysilsesquioxane graft polymers... 

Title Process for Producing Polysilsesquioxane Graft Polymer, Pressure-Sensitive Adhesive, and Pressure-Sensitive Adhesive Sheet... 

A polyhedron silsesquioxane ladder polymer containing polymerizable components was prepared in a three-step process to address this concern. The process initially entailed preparing the reversible addition-fragmentation transfer (RAFT) ladder iniferter, polysilsesquioxane dithiocarbamate. This intermediate was then polymerized with methyl methacrylate at ambient temperature by irradiating with ultraviolet (UV) light and poly(si Isesquioxane-g-methyl methacrylate) was obtained. 

TABLE 1. Physical Properties of Selected Graft Polysilsesquioxane Derivatives... 

An alternate, but less elegant route than that to polysilsesquioxane black glass precursors takes advantage of early work reported by Harrod and coworkers137 on a novel disproportionation reaction (equation 43). When the same catalyst is applied to redistribute a polymethylhydridosiloxane, the result is a processable silsesquioxane polymer (equation 44)138. 

Quasi-solid state dye-sensitized solar cells (DSCs) have been constructed using a new polymeric ionic fluid as the electrolyte.119 The electrolyte was synthesized by the sol-gel route using MTMSPI+I as the precursor that was made by derivatizing methylimidazolium with triethyoxysilane. Condensation of this material in the presence of formic acid and in the absence of water led to Si-O-Si-O-type polymerization and formation of a polysilsesquioxane-type structure. When this material was mixed with iodine, it served as a redox electrolyte for DSCs. The DSCs made this way are robust and easy to assemble but their efficiency of 3.1% is relatively low. However, possible improvement lies in modification of the organic groups attached to the polysilsesquioxane backbone. 

A second method that has been described as a means to deal with the limited accessibility issue involves a copolymerization route. In this approach, the porous matrix is copolymerized with the template. Burleigh and coworkers, for example, described the preparation of imprinted polysilsesquioxanes for the recognition of metal ions.79 Polysilsesquioxanes are hybrid porous materials synthesized from bridged alkoxide precursors such as shown in Figure 20.2.80 In this example, the bridged silsesquioxane precursors were copolymerized with the metal ion complex in the presence of surfactant. Once the surfactant and metal ion were removed, a porous network was formed that showed a high affinity for the metal ion.79... 

The above thermal analysis studies demonstrated the enhanced thermal stability of POSS materials, and suggested that there is potential to improve the flammability properties of polymers when compounded with these macromers. In a typical example of their application as flame retardants, a U.S. patent39 described the use of preceramic materials, namely, polycarbosilanes (PCS), polysilanes (PS), polysilsesquioxane (PSS) resins, and POSS (structures are shown in Figure 8.6) to improve the flammability properties of thermoplastic polymers such as, polypropylene and thermoplastic elastomers such as Kraton (polystyrene-polybutadiene-polystyrene, SBS) and Pebax (polyether block-polyamide copolymer). 

IV. KINETIC CONTROL OF THE SOLID S CHARACTERISTICS OF NANOSTRUCTURED ORGANO-POLYSILSESQUIOXANES R (SiOi.5) ... 

VI. CHEMISTRY INSIDE THE ARCHITECTURE OF THE HYBRID NANOSTRUCTURED ORGANO-POLYSILSESQUIOXANES R/(SiOi5) ... 

We will briefly present the general features concerning the nanocomposite materials and polysilsesquioxanes. We will then focus on the nanostructured materials, their preparation and specific properties, which differ profoundly from the nanocomposites. 

---