New perfectly difunctional organolithium initiators for block copolymer synthesis: Synthesis of dilithium initiators in the absence of polar additives

Properties of block and graft copolymers of polybutadiene with small complexed poly(4‐vinylpyridine) segments

“…The elastomeric block of polybutadiene was first synthesized in pure hexane at room temperature. Initiation was made using either tert-BuLi for the synthesis of diblocks (BP) and of the graft copolymer (BGP) or a dilithium initiator (for triblocks PBP) [13].…”

Ionic Polymerization

“…These sequences depend on the functionality of the initiator (mono-or bifunctional initiators) [172][173][174][175], on the use of coupling agents [176,177], and on the sharpness of the transition between the various blocks. Another reason for apportioning the monomer feed is the limited heat removal capacity of the reactor.…”

Recent Advances in Anionic Polymerization

“…BufCH21Htn-fCH2CH=CHCHz+;Li + n Styrene 2) CH 3 0H) C 6 H 5 (3) This sequential method using a monofunctional initiator cannot be used, however, to synthesize the following A-B-A type of triblock copolymer: (9) 3 to prepare dilithium initiators in hydrocarbon media have resulted in hydrocarbon-insoluble precipitates because of the strong association of organolithium chain ends in hydrocarbon media. A preliminary report has described conditions for efficient preparation and use of this initiator to generate 8 difunctional polymers.…”

“…Other attempts to utilize both soluble and insoluble [9][10][11] dilithium initiators in hydrocarbon media have been reported recently.…”