ORGANOSILOXANE POLYMER

Silicone polymers such as ethoxylated aryl/organosiloxane polymer and siloxane glycol/PAG copolymer also are used occasionally. 

Table 9. Effect of organic substituents on the solubility parameter and the glass transition temperature of an organosiloxane polymer...

Organosiloxane oligomers, in silicone polymerization, 22 555-556 Organosiloxane polymers, silicone resins as, 22 586-590... 

Looking ahead to Section 18.4, explain why isotacticity is not achievable by standard methods of organosiloxane polymer production. 

More extensive use is made of this type of cross linking through trifunctional groups in the organosiloxane polymers, as is shown later. 

As the organosiloxane polymers grow by the process of condensation, the number of hydroxyl groups falls off rapidly, and effective collisions become much less frequent. Heat then must be applied to... 

This method has given results of acceptable reproducibility with a wide variety of organosiloxane polymers, although each type of polymer has its optimum temperature of oxidation in the combustion tube. In general, the oxidation temperatures for polymers with... 

HFC reaction between 1,5-dichlorohexaorganocyclotetrasiloxanes and appropriate dihydroxyde-rivatives in the presence of hydrogen chloride acceptor has synthesized beadshaped cyclolinear organosiloxane polymers [27 - 31] in accordance with the general scheme as follows ... 

Comparing phase diagrams of PACS-4 and linear polydialkylsiloxanes, one may easily observe general tendency of Tg and Tinv variation in organosiloxane polymers, for PACS-4 all temperature transitions being shifted towards higher temperatures [43, 44],... 

The first cyclolinear organosiloxane polymer with ethylene bridges between rings was synthesized by hydrosilylation of 1-hydro-3-vinylhexamethylcyclotetrasiloxane. 

Researchers have now learned how to modify organosiloxane polymers by using various alkyl groups in chains of various lengths and conformations to produce a very wide array of products. All are organosiloxanes, but with very... 

Aramaki K. Self-healing mechanism of an organosiloxane polymer film containing sodium silicate and cerium (111) nitrate for corrosion of scratched zinc surface in 0.5 MNaCl. Corrosion Science, 44(7), 1621-1632 (2002). 

Silicone Resins. Silicone resins are an unusual class of organosiloxane polymers. Unlike linear polysiloxanes, the typical silicone resin has a highly... 

The synthesis of useful low-molecular-weight organosiloxane polymers derived from mineral sources has been reported." " The aqueous phase emulsion polymerization of dimethylcyclic monomers D , n = 3—7, has been studied, and mechanisms have been proposed postulating the combined role as initiator-surfactant in systems polymerized by tetra-alkyl ammonium hydroxides."... 

RTV silicone elastomer, an organosiloxane, is one of the most effective encapsulants used for temperature cycling and moisture protection of IC devices. Since World War II, silicones (organosiloxane polymers) have been used in a variety of applications where properties of high thermal stability, hydrophobicity, and low dielectric constant are necessary, e.g., as encapsulants or conformal coatings for integrated circuits. In 1969 it was demonstrated that room temperature vulcanized (RTV) silicones exhibited excellent performance as moisture protection barriers for IC devices and a number of different RTV silicone have been adapted For use in the elec-tronics industry... 

The health and environmental aspects of poly(dimethylsiloxane) fluids have been reviewed. Sea water saturated with poly(dimethylsiloxane) fluid shows no toxic activity against phytoplanktons, molluscs, crustaceans, and fish. The toxicity of the pyrolysis gases from organosiloxane polymer fluids, rubbers, and resins has been shown to be the least toxic from those of 300 materials tested. Two excellent texts have been published on the analysis of silicones both in bulk and additive forms. > A comparative study of techniques for the trace analysis of Si—H and Si—Cl groups in poly(organosiloxane)s shows that levels of 0.01 p.p.m. H and 1.0 p.p.m. Cl bonded to silicon may be determined, ... 

Defoamers, which, when added to a foaming liquid, break down or inhibit the formation of bubbles in the foam, are of course old in the art. Some of these defoaming compositions are a mixture of compounds such as organosiloxane polymers, including silicone oil and/or normally hydrophilic materials that have their surfaces rendered hydrophobic, such as silica. 

Sulfur-Containing Elastomeric Organosiloxane Polymers (with M. A. Deisz), U. S. Patent 2,960,1 92 (i960). 

Organosiloxane Polymers Containing Polydiene Blocks (with A. Rembaum), U. S. Patent 3 051,681f (1962). 

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