Hyperbranched Polyols via Copolymerization of 1,2-Butylene Oxide and Glycidol: Comparison of Batch Synthesis and Slow Monomer Addition
Hyperbranched poly(butylene oxide) polyols have been synthesized by multibranching anionic ring-opening copolymerization of 1,2-butylene oxide and glycidol. Systematic variation of the composition from 24 to 74% glycidol content resulted in a series of moderately distributed copolymers (Đ = 1.41–1.65, SEC), albeit with limited molecular weights in the solvent-free batch process in the range of 900–1300 g mol–1 (apparent Mn determined by SEC with PEG standards). In situ monitoring of the copolymerization kinetics by 1H NMR showed a pronounced compositional drift with respect to the monomer feed, indicating a strongly tapered microstructure caused by the higher reactivity of glycidol. In the …
“Hard” Sphere Behavior of “Soft”, Globular-like, Hyperbranched Polyglycerols – Extensive Molecular Hydrodynamic and Light Scattering Studies
Whether or not hyperbranched polymers behave like quasi “hard spheres” in solution is the subject of numerous fundamental discussions, also motivated by research on the perfectly branched dendrimer...
Hyperbranched Poly(ethylene glycol) Copolymers: Absolute Values of the Molar Mass, Properties in Dilute Solution, and Hydrodynamic Homology
Hyperbranched poly(ethylene glycol) copolymers were synthesized by random anionic ring-opening multibranching copolymerization of ethylene oxide with glycidol as a branching agent, leading to poly(ethylene glycol) structure with glycerol branching points. Extending the available range of molar masses by novel synthesis strategies, a limited extent of control over the degree of polymerization was achieved by variation of the solvent in this copolymerization. Generally, absolute molar mass characterization of hyperbranched polymers still represents an unresolved challenge. A series of the hyperbranched poly(ethylene glycol)-co-(glycerol) copolymers (hbPEGs) of a wide range of molar masses (14…