High Performance Poly(styrene-b-diene-b-styrene) Triblock Copolymers from a Hydrocarbon-Soluble and Additive-Free Dicarbanionic Initiator

Abstract

A new hydrocarbon-soluble (additive-free) dicarbanionic organolithium initiator, obtained by a simple halogen-lithium exchange reaction (Gilman's reaction) from a diarylhalide containing a side C15 alkyl chain, has been designed and used to initiate the anionic polymerization of butadiene and styrene. The dilithiated species formed afford well-defined poly(styrene-b-butadiene-b-styrene) (SBS) triblock copolymers with a high percentage of 1,4-microstructure polybutadiene (91%) and excellent mechanical properties, such as ultimate tensile strength higher than 30 MPa and elongation at a break of 1000%. This represents a breakthrough in the synthesis of SBS polymers, one of the most used thermoplastic elastomers.

Preparation of polystyrene–polyolefin multiblock copolymers by sequential coordination and anionic polymerization

“…The DM w values were relatively small (5 or 12 kDa) when benzyl-Li(tmeda) 2 was fed as an initiator in amounts of 400 and 500 mmol; benzyl-Li(tmeda) 2 is not as good an initiator as nBuLi(tmeda) 2 for successful execution of the strategy. When divinylbenzene is used, much higher DM w values are expected due to connection of the growing block copolymer chains; however, the observed DM w values were not so very high (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25). The polymerization solution turned turbid at an early stage of the anionic polymerization, indicating that the generated block copolymers are insoluble and form micelles.…”

“…In industry, SEBS is not produced directly from olen and styrene monomers, but, instead, is generated via hydrogenation of PS-block-poly(1,4-butadiene)-block-PS (SBS), which is produced by anionic living polymerization of 1,4-butadiene and styrene (Scheme 1(a)). [7][8][9][10] The hydrogenation process is not an easy task and is a signicant contributor to the manufacturing cost in the production of SEBS. Hence, preparation of PO-PS block copolymers directly from olen and styrene monomers is a worthwhile and formidable pursuit.…”

A New Strategy for the Synthesis of Hydroxyl Terminated Polystyrene-b-Polybutadiene-b-Polystyrene Triblock Copolymer with High Cis-1, 4 Content

“…Currently, anionic polymerization is the most common method for the preparation of SBS copolymers [1]. However, this approach presents some disadvantages.…”

A novel synthetic strategy for styrene–butadiene–styrene tri-block copolymer with high cis -1,4 units via changing catalytic active centres

“…Matmour et al . [16] first reported using a dilithiated initiator in the synthesis of SBS in the absence of additives to obtain a tri-block copolymer with a high 1,4-unit content (91%), but the cis -1,4 structure content was only 41%.…”