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Polydimethylsiloxane (PDMS), also known as dimethylpolysiloxane or dimethicone, is a silicone polymer with a wide variety of uses, from cosmetics to industrial lubrication and passive daytime radiative cooling. [1] [2] [3] PDMS is particularly known for its unusual rheological (or flow) properties.
Polydimethylsiloxane is a prevalent siloxane. In organosilicon chemistry, a siloxane is an organic compound containing a functional group of two silicon atoms bound to an oxygen atom: Si−O−Si. The parent siloxanes include the oligomeric and polymeric hydrides with the formulae H[OSiH 2] n OH and [OSiH 2] n. [1]
TMS is a contaminant in the atmospheres of spacecraft, where it arises from the degradation of silicone-based materials. [5] Specifically, it is the volatile product from the hydrolysis of polydimethylsiloxane, which are generally terminated with trimethylsilyl groups:
The original coral-colored Silly Putty is composed of 65% dimethylsiloxane (hydroxy-terminated polymers with boric acid), 17% silica (crystalline quartz), 9% Thixatrol ST (castor oil derivative), 4% polydimethylsiloxane, 1% decamethyl cyclopentasiloxane, 1% glycerine, and 1% titanium dioxide. [6] Silly Putty flowing through a hole
Particular silicone compounds, cyclic siloxanes D 4 and D 5, are air and water pollutants and have negative health effects on test animals. [31] They are used in various personal care products. The European Chemicals Agency found that "D 4 is a persistent, bioaccumulative and toxic (PBT) substance and D 5 is a very persistent, very ...
Polymethylhydrosiloxane (PMHS) is a polymer with the general structure [−CH 3 (H)Si−O−].It is used in organic chemistry as a mild and stable reducing agent easily transferring hydrides to metal centers and a number of other reducible functional groups.
Silyl-modified polymers (SMP; also silane-modified polymers, modified-silane polymers, MS polymers, silane-terminated polymers, etc.) are polymers terminating with a silyl group. SMPs are the main components in solvent-free and isocyanate-free sealant and adhesive products. [1]
Radical polymerisation of unsaturated monomers is generally propagated by C-radicals. These can be effectively terminated by combining with other radicals to form neutral species and many true inhibitors operate through this mechanism. In the simplest example oxygen can be used as it exists naturally in its triplet state (i.e. it is a diradical).