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

Abstract

A styrene–butadiene–styrene tri-block copolymer (SBS) with a high cis -1,4 unit content (greater than 97%) was synthesized by a novel synthetic strategy based on changing the catalytic active centres using n -butyllithium and a nickel-based catalyst. Firstly, styrene was polymerized via anionic polymerization using butyllithium as the initiator (Li, activity centre Li) at 50°C. The obtained alkylated macroinitiator (PSLi) was aged with nickel naphthenate (Ni) and boron trifluoride etherate (B) to prepare a second reactive centre (Ni-F), which was used to initiate the polymerization of butadiene (Bd). Finally, triphenyl phosphine (PPh 3 ) was added to adjust the electron density of the third active centre (P-Ni-F), and styrene monomer was added again to synthesize the second polystyrene block to obtain SBS. The polymerization technique presented here is simple and has an efficient initiation effect due to the high initiation activities for the different monomers. It also exhibits excellent control over the stereo-structure of the butadiene segments in the prepared copolymers, and the SBS polymers with high cis -1,4 unit content were easily achieved.

Anionic polymerizations in a microreactor

“…107–109 PS- b -PB- b -PS (SBS) represents a class of high-performance elastomers. 110–113 Efficient synthesis of well-defined block copolymers is a critical application of anionic polymerization in a microreactor. 114–118…”

Scandium-catalyzed stereoselective block and alternating copolymerization of diphenylphosphinostyrenes and isoprene

“…In the past decades, enormous efforts have been devoted to the copolymerization of styrene with dienes, affording a considerable number of styrene-diene copolymers with diverse structures. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] Moreover, the copolymerization of polar styrenes with dienes has been successfully achieved by free radical polymerization 17 and living anionic polymerization. [18][19][20] Although coordination polymerization is favourable to adjust the regio-and stereoselectivity of copoly-merization, 21 the active species are prone to be poisoned by polar groups in many cases.…”

Thermal Properties and Self-Assembly Behaviors of Triblock Copolymers Consisting of PEG Segment and Acrylamide-Based Block Bearing Alkyl Side Chains Prepared by RAFT Method

“…Molecular design of block copolymers (BCs) consisting of two or more immiscible polymer segments is the focus of enormous research works in the current decade. − BCs with well-defined structures − and excellent control over their molecular weight and molecular weight distribution are capable of forming various ordered nanostructures − in the thin films through the self-assembly of different segments. Interestingly, the BCs allow their one component to generate hexagonally packed cylinders, spheres arranged in a cubic face-/body-centered lattice, bicontinuous gyroids, or lamellar structure in the matrix of the other component. − Therefore, much effort is devoted to apply these ordered nanostructures to different fields, including nanoporous membranes, − nanotechnology, − nanoscience, − nanofilters, − biomaterials, − and electronic and lithographic nanotemplates. − The dominant factors that govern the microphase-separated nanostructure of block copolymer are the volume fraction of different blocks, the Flory–Huggins interaction parameter, the annealing process, the order of liquid crystals, as well as the solvent used in casting and annealing procedures. − However, the solvent vapor annealing (SVA) treatment is used more frequently in recent times as an alternative to thermal annealing to improve the degree of order or change the orientation of microdomains.…”