End Group Functionality of 95–99%: Epoxide Functionalization of Polystyryl‐Lithium Evaluated via Solvent Gradient Interaction Chromatography

Abstract

End group functionality is a key parameter of functional polymer chains. The end-capping efficiency of living polystyryl lithium with various epoxides, namely ethylene oxide (EO), ethoxy ethyl glycidyl ether (EEGE) and isopropylidene glyceryl glycidyl ether (IGG), is investigated with solvent gradient interaction chromatography (SGIC). Generally, end-capping efficiencies >95% are observed. Hydroxy functional polystyrene (PS-OH, PS-EEGE-OH, and PS-IGG-OH) with molar masses ranging from 13.8 to 15.0 kg mol −1 are obtained, with dispersities of 1.05-1.06. Deprotection of the acetal (PS-EEGE-OH) and ketal protective group (PS-IGG-OH) is investigated. Nearly quantitative deprotection (>99%) resulting in the corresponding multihydroxy functional PS (PS-(OH) 2 and PS-(OH) 3 ) are observed via SGIC. Esterification of PS-OH with succinic anhydride shows a conversion of 98% to the corresponding ester. A detailed picture of side reactions during the carbanionic polymer synthesis subsequent epoxide termination is obtained, demonstrating 95-99% terminal functionality. Depending on the polarity of the end group, an elution order of PS-OH < PS-(OH) 2 < PS-(OH) 3 < PS-COOH is obtained in SGIC. The study demonstrates both the analytical power of SGIC and the exceptionally high terminal functionalization efficiency of anionic polymerization methods.

Bifunctional Carbanionic Synthesis of Fully Bio‐Based Triblock Structures Derived from β‐Farnesene and ll‐Dilactide: Thermoplastic Elastomers

“…Polyfarnesyl lithium was transformed to hydroxy functional telechelics by end‐functionalization of the living chain ends with a glycidyl ether, namely ethoxy ethyl glycidyl ether (EEGE). After acidic deprotection, telechelic tetrahydroxy macroinitiators with a high degree of end‐functionalization are accessible in a highly controlled manner [21] . The targeted 100 % bio‐based A 2 BA 2 ‐type triblock‐type structure was further generated by polymerization of ll ‐dilactide (LLA), one of the most abundant bio‐based materials to date.…”

Bifunktionelle carbanionische Synthese vollständig biobasierter Triblock‐Copolymere aus β‐Farnesen und LL‐Dilactid: Thermoplastische Elastomere

“…Polyfarnesyllithium wurde durch Endfunktionalisierung der lebenden Kettenenden mit dem Glycidylether Ethoxyethyl‐glycidylether (EEGE) zu hydroxy‐funktionellen Telechelen umgesetzt. Nach saurer Abspaltung der Schutzgruppe sind telechele Tetrahydroxy‐Makroinitiatoren mit einem hohen Endfunktionalisierungsgrad über eine sehr kontrollierte Synthese zugänglich [21] . Die angestrebte vollständig biobasierte A 2 BA 2 ‐Triblockstruktur wurde anschließend durch Polymerisation von ll ‐Dilactid (LLA) zu Poly‐( l )‐Lactid (PLLA), einem der gängigsten biobasierten Materialien, erhalten.…”

“…Nach saurer Abspaltung der Schutzgruppe sind telechele Tetrahydroxy-Makroinitiatoren mit einem hohen Endfunktionalisierungsgrad über eine sehr kontrollierte Synthese zugänglich. [21] Die angestrebte vollständig biobasierte A 2 BA 2 -Triblockstruktur wurde anschließend durch Polymerisation von LL-Dilactid (LLA) zu Poly-(L)-Lactid (PLLA), einem der gängigsten biobasierten Materialien, erhalten. Der hohe T g von PLLA von � 60 °C prädestiniert es für den Einsatz als glasartige äußere Blöcke von TPEs.…”

Synthesis and Characterization of Spirocyclic Mid-Block Containing Triblock Copolymer

“…In this case, prep SEC is limited to the isolation of cyclic products. Recently, advances in liquid chromatography under critical conditions (LCCC) have enabled the separation of polymer mixtures based on their functionalities, regardless of their molecular weights [ 27 , 28 ]. For example, with an increase in the number of polar functionalities of the polystyrene chains, the elution time increases in solvent gradient liquid chromatography [ 27 ].…”

“…Recently, advances in liquid chromatography under critical conditions (LCCC) have enabled the separation of polymer mixtures based on their functionalities, regardless of their molecular weights [ 27 , 28 ]. For example, with an increase in the number of polar functionalities of the polystyrene chains, the elution time increases in solvent gradient liquid chromatography [ 27 ]. In addition, the LCCC technique has been successfully applied to the purification of cyclic polymers [ 29 , 30 ].…”