Hetero‐Multifunctional Poly(ethylene glycol) Copolymers with Multiple Hydroxyl Groups and a Single Terminal Functionality

Abstract

Hetero-multifunctional poly(ethylene glycol-co-glycerol) random copolymers with multiple hydroxyl functionalities and a single terminal functionality have been prepared by copolymerization of ethylene oxide (EO) and ethoxy ethyl glycidyl ether (EEGE) with the use of a suitable initiator, introducing a protected amino group or a double bond, respectively. Acidic deprotection was used for removal of the acetal protecting groups in the chain, and the terminal amino group was regenerated by catalytic hydrogenation. A series of copolymers with narrow polydispersity was obtained, varying comonomer fractions from 3 to 67% and molecular weights in the range of 5 000-32 000 g · mol(-1) (1.05 < $\overline M _{\rm w} /\overline M _{\rm n}$ < 1.25). Molecular and thermal characterization was carried out using (1) H- and (13) C NMR, SEC and differential scanning calorimetry (DSC).

Reactivity Ratios and Mechanistic Insight for Anionic Ring-Opening Copolymerization of Epoxides

“…Numerous investigations of the copolymerization of functional glycidyl ethers with ethylene oxide have recently been reported,[7-10, 31, 33] with most of the reports concluding that the sequence distribution of the copolymers was random based on triad analysis in 13 C NMR spectroscopy. No comparison was made, however, with reactivity ratio dependent triad probabilities derived by Heatly et al .…”

“…As a result, this new technique provides a more direct and conclusive spectroscopic measurement than the specific, qualitative 13 C NMR spectroscopy-based method adopted by others for copolymerizations of EO and glycidyl ethers. [7-10, 31, 33]…”

Multifunctional Poly(ethylene glycol)s

“…[86] Thus, linear copolymers of EO and 1-ethoxy ethyl glycidyl ether (EEGE), yielding random poly(ethylene oxideco-glycerol) (P(EO-co-G)) after acidic deprotection, represent the most common access to mf-PEGs. [57,70,74,75,[87][88][89][90][91][92][93][94] The living copolymerization of EO and EEGE guarantees excellent control over molecular weights and narrow molecularweight distributions with polydispersity indices (M w /M n ) commonly below 1.10. Most interestingly, the expected biocompatibility of hydroxy mf-PEG was demonstrated in Figure 1.…”

(1‐Adamantyl)methyl Glycidyl Ether: A Versatile Building Block for Living Polymerization

“…The AdaGE content used in the starting monomer mixture was also found in the final copolymer composition. Based on our previous work on the kinetics of glycidyl ether copolymerization, the copolymers of EEGE and AdaGE are most likely random copolymers. Acidic cleavage of the acetal protection group of EEGE (Figure S20, Supporting Information) leads to linear polyglycerols with pendant adamantyl groups ( lin PG‐ co ‐PAdaGE) (Table ).…”