Tadeusz Biedroń

Atom-Transfer Radical Polymerization of Acrylates in an Ionic Liquid

The atom-transfer radical polymerization (ATRP) of acrylates in 1-butyl-3-methylimidazolium hexafluorophosphate was investigated. The solubility of the acrylates in the ionic liquid depends on the substituent. The homogeneous polymerization of methyl acrylate gives polymers with Mn close to the calculated value and relatively narrow polydispersity. In heterogeneous polymerizations of higher acrylates, with the catalyst present in the ionic liquid phase, deviations from ideal behavior are observed although the polymerization of butyl acrylate approaches the conditions of a controlled polymerization.

Branched polyether with multiple primary hydroxyl groups: polymerization of 3-ethyl-3-hydroxymethyloxetane

Cationic polymerization of 3-ethyl-3-hydroxymethyloxetane gives branched, soluble macromolecules with multiple glycolic end groups. There are approximately 3–4 “normal” units per one branched unit.

Studies of atom transfer radical polymerization (ATRP) of acrylates by MALDI TOF mass spectrometry

Atom transfer radical polymerization (ATRP) of methyl, butyl and tert-butyl acrylates was studied at conditions when low molecular weight polymers (M n ≅ 2 . 10 3 ) are formed, i.e., at relatively high concentration of initiator (ethyl 2-bromopropionate) and calatyst (CuBr/amine). MALDI TOF analysis of the polymer samples isolated at different stages of polymerization revealed that in the course of polymerization potentially active macromolecules terminated with bromine are gradually converted into inactive macromolecules devoid of terminal bromine. A possible transfer mechanism, involving amine is a component of the catalytic system, is proposed. It was shown that quantitative analysis of the MALDI TOF spectra allows one to estimate the ratio of apparent rate constants of propagation and degradative transfer, providing quantitative information to what extent the system conforms to the controlled polymerization scheme.

Synthesis of block copolymers by atom transfer radical polymerization of tert‐butyl acrylate with poly(oxyethylene) macroinitiators

Poly(oxyethylene)s terminated at both ends with 2-bromopropionate end-groups were prepared and characterized by means of MALDI TOF mass spectrometry. It was shown, that atom transfer radical polymerization (ATRP) of methyl methacrylate with a poly(oxyethylene) macroinitiator in bulk proceeds with low initiation efficiency while polymerization of tert-butyl acrylate proceeds with practically quantitative initiation, leading to ABA block copolymers. Originally formed tert-butyl acrylate blocks contain terminal bromine, as expected for the ATRP mechanism. MALDI TOF analysis indicates, however, that in the later stages of polymerization side reactions lead to elimination of terminal bromine.

Aggregation of polylactide with carboxyl groups at one chain end in the presence of metal cations

Polylactides with one or more carboxyl groups at one chain end were synthesized by cationic polymerization according to activated monomer mechanism and by application of “thiol-yne” click chemistry for subsequent functionalization. End groups of such obtained polylactides were converted into ionic groups by neutralization of polymer solutions with metal oxides, mainly calcium oxide, and the aggregation of individual stereoisomers as well as that of the mixture of poly(l-lactide) (PLLA) and poly(d-lactide) (PDLA) was investigated. The extent and progress of the aggregation was followed by viscosity measurements, and aggregated polymers in the solid state were examined by SEM and DSC. Solution viscosity increase was observed upon the aggregation of individual PLA stereoisomers, whereas PLA stereocomplex precipitation occurred in the case of the aggregation of PLLA/PDLA/metal oxide mixture.

Ring‐opening polymerization processes involving activated monomer mechanism. Cationic polymerization of cyclic ethers containing hydroxyl groups.

Cationic polymerization of cyclic ethers containing hydroxyl groups as substituents is discussed in terms of contribution of Active Chain End (ACE) and Activated Monomer (AM) polymerization mechanisms.

Application of poly(oxyethylenes) containing terminal phosphonium ion groups as phase transfer reaction catalysts

Abstract The activity of poly(oxyethylenes), terminated at both ends with phosphonium ion groups, as catalysts in phase transfer reaction has been compared with this of the nonionic analogs. The observed moderate enhancement of activity for diionically terminated poly(oxyethylenes) may be attributed to increasing alkali metal complexing ability, due to the intramolecular aggregation of the ionic end-groups resulting in the formation of cyclic structure.