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Silyl Triflate-Initiated Ring-Opening Polymerizations of Cyclosiloxanes (1998)

Jallouli, Aref ; Saam, John C.

Springer

Journal of inorganic and organometallic polymers and materials 8 (1998), S. 179-203

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ISSN: 1572-8870

Keywords: Trimethylsilyl trifluoromethanesulfonate ; 1,3,5-trimethyl-1,3,5-tris(3′,3′,3′-trifluoropropyl)cyclotrisiloxane ; hexamethylcyclotrisiloxane ; poly(dimethylsiloxane) ; poly[methyl(3,3,3-trifluoropropyl)siloxane] ; ring-opening polymerization

Source: Springer Online Journal Archives 1860-2000

Topics: Chemistry and Pharmacology

Notes: Abstract Polymer yields between 70 and 85% form in ring-opening polymerizations of trimeric cyclosiloxanes initiated with trimethylsilyl triflate in the presence of a selective scavenger for protic acids, 2,6-di-t-butylpyridine. Examples include the polymerization of 1,3,5-trimethyl-1,3,5-tris(3′,3′,3′-trifluoropropyl)cyclotrisiloxane (F3) and hexamethylcyclotrisiloxane (D3). Siloxane bond redistribution is essentially absent and data are presented establishing a nonterminating polymerization giving an average of roughly one trimethylsilyl group per chain. The present observations contrast with other work that suggests that the presence of free triflic acid is required for initiation with trimethylsilyl triflate.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1023/A:1021479909180

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Stereoregularity in poly[methyl(3,3,3-trifluoropropyl)siloxane]Dedicated to Professor Maurice Morton to commemorate the establishment of the Maurice Morton Institute of Polymer Science at the University of Akron. (1994)

Kuo, Chung-Mien ; Saam, John C. ; Taylor, Richard B.

New York, NY [u.a.] : Wiley-Blackwell

Polymer International 33 (1994), S. 187-195

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ISSN: 0959-8103

Keywords: poly[methyl(3,3,3-trifluoropropyl)siloxane] ; cis- or trans-1,3,5-trimethyl-1,3,5-tris(3′,3′,3′-trifluoropropyl)cyclotrisiloxane ; ring-opening polymerization ; stereoregularity ; tacticity ; crystallinity ; Chemistry ; Polymer and Materials Science

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics

Notes: Anionic ring-opening polymerization of the cis and trans isomers of 1,3,5-trimethyl-1,3,5-tris(3′,3′,3′-trifluoropropyl)cyclotrisiloxane (cis- and trans-F3) and their mixtures was conducted under conditions that suppressed siloxane bond redistribution in order to preserve stereoregularity formed in the resulting poly[methyl(3,3,3-trifluoropropyl)siloxane] (PMTFPS). Proton decoupled 19F NMR of the resulting polymers was interpreted by assuming that the original stereoconfiguration of the monomer was preserved and that the monomer inserted with a roughly equal probability of forming meso or racemic configurations relative to the configuration of the reacting chain end. Polymers from cis-F3 were solid and crystalline at room temperature while the more typical polymers from mixtures of isomers containing greater than 50% trans-F3 were liquid and amorphous.

Additional Material: 9 Ill.