In situ stabilizer formation from methacrylic acid macromonomers in emulsion polymerization
| Autor: | Jpa Johan Heuts, Ingeborg Schreur-Piet |
|---|---|
| Přispěvatelé: | Materials and Interface Chemistry, Macromolecular and Organic Chemistry |
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Polymers and Plastics
Chemistry Organic Chemistry technology industry and agriculture Emulsion polymerization Bioengineering Chain transfer 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Biochemistry 0104 chemical sciences chemistry.chemical_compound Polymerization Catalytic chain transfer Polymer chemistry Copolymer Reversible addition−fragmentation chain-transfer polymerization Methyl methacrylate 0210 nano-technology Ionic polymerization |
| Zdroj: | Polymer Chemistry, 8(43), 6654-6664. Royal Society of Chemistry |
| ISSN: | 1759-9962 1759-9954 |
| Popis: | Oligomers of methacrylic acid containing a propenyl ω-endgroup (i.e. MAA-macromonomers) were synthesized by cobalt-mediated catalytic chain transfer polymerization and used as precursors to stabilizers in emulsion polymerization. It was found that only in those polymerizations in which these precursors were sufficiently quickly converted into amphiphilic molecules, via a type of polymerization induced self-assembly (PISA) mechanism, stable emulsion polymerization could be carried out. This process was too slow in the emulsion polymerization of methyl methacrylate (MMA) and in order to obtain stable latexes, the addition of a conventional surfactant (sodium dodecyl sulphate, SDS) was necessary. In the emulsion polymerization of butyl acrylate, however, reactions with the macromonomers were faster and because of the more hydrophobic nature of BA (as compared to MMA), stabilizers were sufficiently quickly formed in situ and stable latexes were produced without the need for additional SDS. Also the emulsion polymerization of butyl methacrylate (BMA), which reacts via the same "sulfur-free RAFT" mechanism as MMA, could be carried out in the absence of SDS because of the greater hydrophobicity of the monomer. Copolymerizations of MMA with >30% of BA or 85% BMA also resulted in stable latexes without the addition of SDS. The synthesized macromonomers and in situ formed copolymers were characterized by means of size exclusion chromatography (SEC), 1H NMR spectroscopy and MALDI-ToF MS. |
| Databáze: | OpenAIRE |
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