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## Study on the synthesis and morphology of branched copolymers synthesized by controlled radical polymerization methods

### Konraf Grygiel

#### Abstract

Symmetric and asymmetric star polymers containing high number of arms were synthesized in a few-step reactions, which was the main goal of this research. It was necessary to obtain multifunctional macroinitiators for Atomic Transfer Radical Polymerizations (ATRP). For this reason, hydroxyl end groups of Boltorn H30 were transformed into halogen groups. Elemental analysis and H NMR techniques confirmed high average amount of initiating species (over 20) per molecule. Then, poly(methyl acrylate) (PMA) symmetric star homopolymers (SH) with narrow molecular weight distribution were successfully synthesized using Atom Regenerated by Electron Transfer (ARGET) ATRP technique. Obtaining SH was followed by subsequent chain extension reactions with tert-butyl acrylate (tBA). Regular PMA-PtBA star block copolymer was synthesized and characterized. Star block copolymer consisted of 16 wt. % of PMA and in 84 wt. % of PtBA. Hydrolysis reactions of tert-butyl groups in peripheral blocks led to obtaining of interesting product, which was able to form suspensions in polar solvents. Synthesis of multiarm asymmetric star polymers was successfully carried out. Optimization of catalyst concentration in ARGET ATRP systems was essential to reach broad molecular weight distribution of star polymers’ arms. Suppressing of side reactions was challenging and did not succeed. Modyfing macroinitiator concentration and composition of reaction mixture did not solve the problem of recombination and disproportionation of radicals. Side reactions resulted in the formation of polymer gels and networks. Therefore, that chain extension reactions of asymmetric star polymers via ARGET ATRP with tBA did not succeed. The series of hydrolysis reaction of SH’s core was carried out at different conditions. The goal was to separate polymer arms from the core, which could be an excellent way to characterize them in the terms of molecular weight distributions. Arms of SH were partly hydrolyzed, but it was insufficient to make a precise and direct analysis of polymer arms. An attempts were made to create conditions for self-assembly of regular star copolymer into periodic microdomain morphology. Polymer films were characterized using SAXS, but no morphological structure was identified. Three factors might have caused the problem: too small volume fraction of PtBA block, polymer network formed by macromolecules and specific phase diagram for star copolymers. Summarizing, the potential of ARGET ATRP in synthesis of regular and asymmetrical star polymers containing high amount of arms was confirmed. Some problems were also pointed, which are really hard to avoid, as long as “core-first” polymerization strategy is employed.
Record ID
Diploma type
Master of Science
Author
Konraf Grygiel Konraf Grygiel,, Undefined Affiliation
Title in Polish
Supervisor
Andrzej Plichta (FC/CPCT) Andrzej Plichta,, Chair Of Polymer Chemistry And Technology (FC/CPCT)Faculty of Chemistry (FC)
Certifying unit
Faculty of Chemistry (FC)
Affiliation unit
Chair Of Polymer Chemistry And Technology (FC/CPCT)
Study subject / specialization
, Technologia Chemiczna
Language
(pl) Polish
Status
Finished
Defense Date
30-07-2012
Issue date (year)
2012
Keywords in Polish
-
Keywords in English
-
Abstract in Polish
urn:pw-repo:WUTad1d4275db944670aec7dad91ad976ca