Improvement in alkoxide anionic initiation technique by using a colorimetric titration

Abstract

ABSTRACT:We developed a colorimetric method to follow and to control the complete transformation of an alcohol into an alkoxide. It was first tested on a small molecule and then extended to a macroinitiator. It allows us to obtain a final product without residual prepolymer and without side initiation due to an excess of carbanion. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1339 -1343, 2005

Synthesis of PS(PEO)3 star block copolymers from a heterotetrafunctional initiator

“…18 Polymerization of EO used to run in THF at 35 8C during 48 h. As shown by the SEC traces, no side reaction of the DPMK on the ester function, leading to a mixture of homoPS and PEO star, took place. So, this way, and for the first time, PS(PEO) 3 star block copolymers with relatively low polydispersity indices were obtained (1.3 < PDI < 1.4) ( Table 2).…”

“…Then, diphenyl methyl potassium (DPMK) (prepared according to the classical procedure 17 ) (0.652 mol/L) was added dropwise at À70 8C, until the medium turned to orange. 18 Around 3.8 g of EO (8.6 3 10 À2 mol) were then introduced in the reactor under vacuum and the polymerization was run at 35 8C during 48 h. The polymerization was terminated by addition of methanol. The reaction mixture was concentrated, and the copolymer precipitated into diethylic ether, washed with water, filtered, and dried to provide a white powder.…”