Switch from Anionic Polymerization to Coordinative Chain Transfer Polymerization: A Valuable Strategy to Make Olefin Block Copolymers

Abstract

Anionic polymerization of butadiene or/and styrene is performed with lithium initiators, functional or not. The polymer chains are subsequently transferred to magnesium. The resulting polymeryl-magnesium compounds were combined with {(Me 2 Si(C 13 H 8 ) 2 )Nd(μ-BH 4 )[(μ-BH 4 )Li(THF)]} 2 metallocene complex to act as macromolecular chain transfer agents (macroCTAs) in coordinative chain transfer polymerization (CCTP) of ethylene (E) or its copolymerization (CCTcoP) with butadiene (B). Block copolymers were produced for the first time by this switch from anionic polymerization to CCTP. Hard and soft blocks such as PB, polystyrene (PS), poly(styrene-co-butadiene) (SBR) obtained by anionic polymerization and PE or poly(ethylene-cobutadiene) (EBR) produced by CCT(co)P were combined and the corresponding structures were characterized.

Kinetic Modeling of the Synthesis of Poly(4-vinylpyridine) Macro-Reversible Addition-Fragmentation Chain Transfer Agents for the Preparation of Block Copolymers

“…2−4 Despite the versatility of these materials, aside from a few exceptions such as the polymers of styrene-butadiene-styrene (SBS), styreneisoprene-styrene (SIS), or poly(ethylene oxide)−b−poly-(propylene oxide)−b−poly(ethylene oxide) (PEO−b−PPO− b−PEO), not many of them are produced in industrial scales. 1,5 One reason for this is that the synthesis of them usually is done via anionic polymerization, a technique that has high demands on the control of reaction conditions in order to successfully and safely obtain the final polymer with welldefined properties on larger scales. 6−9 Alternatives to anionic polymerization are controlled radical polymerization methods, which are less demanding with respect to reaction conditions.…”

“…Well-defined block copolymers synthesized mainly by anionic polymerization have been used in a broad range of applications and have been an important research field in the last 30 years . These applications range from bulk composite materials, optical materials, polymeric membranes, etc. − Despite the versatility of these materials, aside from a few exceptions such as the polymers of styrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS), or poly­(ethylene oxide)– b –poly­(propylene oxide)– b –poly­(ethylene oxide) (PEO– b –PPO– b –PEO), not many of them are produced in industrial scales. , One reason for this is that the synthesis of them usually is done via anionic polymerization, a technique that has high demands on the control of reaction conditions in order to successfully and safely obtain the final polymer with well-defined properties on larger scales. − …”

Anion Migrated Ring Opening and Rearrangement in Anionic Polymerization Induced C7 and C8 Polymerizations

“…Living anionic polymerization (LAP) is a conventional living polymerization method that plays a crucial role in both academia and industry. − Potential obstacles in the development of LAP, however, are that the available monomers are rare, and all of the resulting products exhibit C2 and C4 skeleton structures, which limit further development of mechanisms and applications. Thus, new polymerization mechanisms and synthetic strategies should be developed over time to advance the field of polymer synthesis.…”