Silicones

Abstract

Silicon are a class of materials with unique properties that make them useful in a variety of applications of commercial interest and support a thriving global industry. This article updates a comprehensive survey of the chemistry and technology of silicones last published in Kirk‐Othmer Encyclopedia of Chemical Technology in 1997. The update contains more than 235 references not cited in the previous version and includes literature published through 2001. A new section dealing with fiber finishing applications has been included in the current version. The review provides an excellent primary reference for this interesting area of chemistry and technology.

Silicone‐Supported Cinchona Alkaloid Derivatives as Insoluble Organocatalysts in the Enantioselective Dimerization of Ketenes

“…In addition, the spectra of the final solution showed neither degradation of the alkaloid core nor significant isomerization of the terminal double bond of 17 to the hydrosilylation-refractory internal positions. [13] The covalent linkage of the chiral unit to PMHS was also confirmed by the growth of two broad res- onances at 23.4 and 17.9 ppm in the 13 C NMR spectrum, which, by comparison with literature values, [14] identified the CH 2 CH 2 Si fragment of the polymer-bound alkaloid.…”

“…The poor solubility of the gelled material hampered a detailed investigation of the phenomenon, which was likely a result of side reactions of the excess Si-H units of PMHS after the complete conversion of the vinyl groups of 17. [13,15] Because the observed phase separation made the preparation of uniform elastomeric films by the previously developed two-step approach unfeasible, [8] an investigation of a single-step procedure was performed. Toluene solutions of 16, 17, or 18, PMHS, low and high molecular-weight divinyl-terminated silicones (PDMS-DV lw and hw, respectively), [8] and the Karstedt catalyst were gently heated overnight under air in a PTFE-lined vessel (Scheme 3).…”

Silicon Acetal Metathesis Polymerization

“…The silicone polydimethylsiloxane (PDMS) is 38% silicon and 22% oxygen and is the most commonly used silicon-containing polymer, having gained considerable attention since the 1940s. PDMS has repeat units of [−OSiMe 2 −] with only Si–O bonds along the backbone . PDMS can be used for many applications, including adhesives, coatings, contact lenses, biomedical devices, lubricating oils, and elastomers. − Important and specific attributes include low glass transition temperature, high conformational flexibility, biocompatibility, high gas permeability, hydrophobicity, and good oxidative, thermal, and UV light stability. , Although PDMS has such valuable characteristics, its relatively poor mechanical properties prevent it from replacing high-volume commodity plastics (e.g., polyethylene, polypropylene, polyvinyl chloride) in a wider variety of consumer applications.…”

“…PDMS has repeat units of [−OSiMe 2 −] with only Si–O bonds along the backbone . PDMS can be used for many applications, including adhesives, coatings, contact lenses, biomedical devices, lubricating oils, and elastomers. − Important and specific attributes include low glass transition temperature, high conformational flexibility, biocompatibility, high gas permeability, hydrophobicity, and good oxidative, thermal, and UV light stability. , Although PDMS has such valuable characteristics, its relatively poor mechanical properties prevent it from replacing high-volume commodity plastics (e.g., polyethylene, polypropylene, polyvinyl chloride) in a wider variety of consumer applications. Therefore, the inexhaustible supplies of silicon and oxygen should be transformed into new polymers with improved and tunable thermomechanical properties. , Moreover, with the increasing availability of plant-based polymer building blocks, there exists an opportunity to fashion these new polymers, stated tersely, from plants and sand.…”

Fluorinated Additives for Rubber

“…A number of good general references for these resins are available, for example [65]. The most common fluorosilicone has a trifluoropropyl (CF 3 CH 2 CH 2 e) group attached to the silicon.…”