Silicone polymers degradation

S. Wallstrom, K. Dowling, and S. Karlsson, Development and comparison of test methods for evaluating formation of biofilms on silicones, Polymer Degradation and Stability, 78(2) 257-262,2002. 

One of the chief uses of chloromethane is as a starting material from which silicone polymers are made. Dichloromethane is widely used as a paint stripper. Trichloromethane was once used as an inhalation anesthetic, but its toxicity caused it to be replaced by safer materials many years ago. Tetrachloromethane is the starting material for the preparation of several chlorofluorocarbons (CFCs), at one time widely used as refrigerant gases. Most of the world s industrialized nations have agreed to phase out all uses of CFCs because these compounds have been implicated in atmospheric processes that degrade the Earth s ozone layer. 

Electron beam inks, 14 314-315 Electron beam irradiation, silicone network preparation via, 22 567 VDC polymer degradation via, 25 713 Electron beam lithography... 

Nonplant cost, 9 527 Nonpoint contamination source, 13 310 Nonpolar adsorbents, 1 674 for gas adsorption, 1 632 Nonpolar solvents, VDC polymer degradation in, 25 717-718 Nonporous dense membranes, 15 799 Nonporous silicone tubing, flow through, 15 722, 723... 

POLYDIMETHYLSILOXANE. A silicone polymer developed for use as a dielectric coolant and in solar energy installations, It also may have a number of other uses. It is stated to be highly resistant to oxidation and biodegradation by microorganisms. It is degradable when exposed to a soil environment by chemical reaction with clays and water, by which it is decomposed to silicic acid, carbon dioxide, and water. 

J.R. Ebdon, B.J. Hunt, M.S. Jones, and F.G. Thorpe, Chemical modification of polymers to improve flame retardance. II. The influence of silicon-containing groups, Polym. Degrad. Stab., 54, 395M-00 (1996). 

Ebdon, J.R., Hunt, B.J., and Joseph, P., Thermal degradation and flammability characteristics of some polystyrenes and poly(methylmethacrylate)s chemically modified with silicon-containing groups, Polym. Degrad. Stab. 2004, 83, 181. 

Multiple Quantum NMR methods have been used to characterize the results of multiple degradation mechanisms on complex silicone polymer composites. 

The stmctural architecture of silicone polymers, such as the number of D, T, and Q sites and the number and type of cross-link sites, can be determined by a degradative analysis technique in which the polymer is allowed to react with a laige excess of a capping agent, such as hexamethyldisiloxane, in the presence of a suitable equilibration catalyst (eq. 38). Triflic acid is often used as a catalyst because it promotes the depolymerization process at ambient temperature (444). A related process employs the KOH- or KOC2H -catalyzed reaction of silicones with excess Si(OC2H5)4 (eq. 39) to produce ethoxjiated methjisilicon species, which are quantitatively determined by gc (445). 

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