Silyl ester initiators for ring opening polymerization of cyclos

Details Silyl ester initiators for ring opening polymerization of cyclos Silyl ester initiators for ring opening polymerization of cyclos

1997-05-28

1998-11-03

Smith, Jeffrey T.

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

From silicon reactant having at least one...

528 23, 528 42, C08G 7708

Patent

active

058309691

ABSTRACT:
Method of making polysiloxanes by ring opening polymerization of dimethylcyclosiloxanes such as hexamethylcyclotrisiloxane (D.sub.3), and cyclosiloxanes such as 1,3,5-trimethyl-1,3,5-tris(3',3',3'-trifluoropropyl) cyclotrisiloxane (F.sub.3) or 1,3,5,7-tetramethyl-1,3,5,7-tetrakis(3',3',3'-trifluoropropyl) cyclotetras iloxane (F.sub.4) in an acid-free system using electrophillic initiators. The reaction mixture is formed under anhydrous conditions and contains (i) the cyclosiloxanes, (ii) a Lewis base such as 2,6-di-tert-butylpyridine which serves as a co-catalyst and an acid scavenger, and optionally (iii) a salt of a strong acid such as tetrabutylammonium trifluoromethane sulfonate. The anhydrous mixture is contacted with a silyl ester of a strong acid such as triflic acid. The anhydrous reaction mixture is agitated at room temperature until a polysiloxane is formed. Polymerization can be initiated practically immediately after introduction of the cyclosiloxanes, by first adding the Lewis base to the silyl ester, and allowing the Lewis base and the silyl ester to interact.

REFERENCES:
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patent: 3373138 (1968-03-01), Brown
patent: 3974120 (1976-08-01), Razzano et al.
patent: 5401822 (1995-03-01), Collins
patent: 5696219 (1997-12-01), Jallouli et al.
Journal of Polymer Science: Part A: Polymer Chemistry, vol. 33, 285-298, (1995).
Macromol. Chem. Phys., 196, 2715-2735, (1995).

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