Partner: Holger Frey

Johannes Gutenberg University (DE)

Recent publications
1.von Tiedemann P., Maciol K., Preis J., Sajkiewicz P., Frey H., Rapid One-Pot Synthesis of Tapered Star Copolymers via Ultra-Fast Coupling of Polystyryllithium Chain Ends, Polymer Chemistry, ISSN: 1759-9954, DOI: 10.1039/C8PY01656A, pp.1-7, 2019
Abstract:

Highly efficient stoichiometric coupling of sterically hindered polystyryllithium (PS-Li) chain ends was achieved using tetra[3-(chloro-dimethylsilyl)propyl]silane (TCDMSPS) as the linking agent. Based on the disparate reactivities of isoprene (I, rI = 11.0) and styrene (S, rS = 0.049) in the anionic copolymerization in nonpolar media, poly(isoprene0.5-grad-styrene0.5) (P(I0.5-grad-S0.5)) tapered 4-arm star copolymers were synthesized in only two steps. The tapered 4-arm star copolymers (Mwtargeted = 40 to 160 kg mol-1) were synthesized with high star functionalities f (Mw,star/Mw,arm = 3.68 – 3.98), low dispersity (Ð = 1.08 – 1.15) and minimal residual precursor content (2-8 wt%), avoiding fractionation or other purification methods. Coupling kinetics measurements revealed that for the synthesis of polystyrene (PS) 4-arm stars (12 kg mol-1) a coupling efficiency of 98% was already achieved within 2 minutes. All star polymers were analyzed by size exclusion chromatography (SEC) viscometry with universal calibration (UC) as well as NMR spectroscopy. Well-defined nanofibers from the tapered copolymer stars were obtained via electrospinning.

Affiliations:
von Tiedemann P.-Johannes Gutenberg University (DE)
Maciol K.-Johannes Gutenberg University (DE)
Preis J.-PSS Polymer Standards Service GmbH (DE)
Sajkiewicz P.-IPPT PAN
Frey H.-Johannes Gutenberg University (DE)