No abstract

Protected polyglycidols with a linear or star-shaped architecture were obtained via anionic ring-opening polymerization of protected glycidol in diglyme with potassium as counterion. Removal of the protecting groups lead to polyglycidols, which were used as multifunctional macroinitiators for the chemically and enzymatically catalyzed ring-opening polymerization of ε-caprolactone. For the chemically catalyzed polymerization zinc(II) 2-ethylhexanoate was used, while Novozyme 435 (Lipase B from Candida antarctica immobilized on a macroporous resin) was used for the enzymatically catalyzed polymerization. To determine the characteristics of the two differently catalyzed polymerizations, monofunctional macroinitiators based on poly(ethylene glycol) were applied. The main difference observed was the initiator efficiency, which was explained by the different polymerization mechanism. By using multifunctional macroinitiators the difference in the initiation efficiency lead to different polymer architectures. For the chemically catalyzed polymerization, all hydroxy groups of the polyglycidols initiated polymerization, and core−shell polymers with a hydrophilic polyether core and a hydrophobic polyester shell were obtained. For the enzymatically catalyzed polymerization only 15−20% of the hydroxyl groups initiated the polymerization of ε-caprolactone with the result of a different polymer architecture; these polymers have a hydrophilic polyglycidol head coil with hydrophobic poly(ε-caprolactone) tails.

Primary amine groups of branched poly(ethylene imine) (PEI) were functionalized with quaternary ammonium groups, alkyl chains of different length, allylic and benzylic groups in a one-step reaction, using a carbonate coupler. The structure of the obtained amphiphilic polymers was determined by means of 1H and 13C NMR spectroscopy. Depending on their hydrophilic/hydrophobic balance, the obtained polymers can be used as water-soluble disinfectants and for antimicrobial coating materials. The bactericidal properties of some of the amphiphilic polymers against Gram-negative and Gram-positive bacteria were investigated. Minimal inhibitory concentrations (log 4 reduction of bacterial growth) against Escherichia coli and Bacillus subtilis were determined in the range of 0.3-0.4 mg/mL and 0.03-0.04 mg/mL for water-soluble polymers. Glass slides coated with functionalized PEIs showed a reduction of colony forming units of at least 95%, at best 99.9%, against E. coli and B. subtilis.

No abstract

Linear and star shaped polyglycidols (synonym with polyglycerols) are prepared in a controlled ring opening polymerization of protected glycidols. Beside the molar mass and the polydispersity, the architecture of the polyglycidols is controlled by using mono-and multifunctional monoand polydispers initiators. Copolymers of dissimilarly protected glycidols as well as copolymers with nonfunctional oxiranes were prepared by means of anionic polymerization while copolymers of protected glycidol with tetrahydrofuran were prepared by means of cationic polymerization. Polyethers with functional groups in the side chains (functional polyethers) with special emphasis on polyglycidols (containing hydroxymethyl groups in the side chains) were used to prepare multifunctional polymers and (hetero)grafted polymer brushes via chemical and enzyme catalyzed reaction. The potential of poly(glycidol-graft-e-caprolactone)-co-glycidol) prepared via enzyme catalyzed grafting of polyglycidols using e-caprolactone as a monomer and Lipase B from Candida antarctica as a catalyst is presented. Finally, comparative degradation studies of densely and loosely grafted polyglycidols are presented and discussed.