Thermal Instability Of 2-Phenylprop-2-ylphenyldithioacetate And Macro-Derivatives In RAFT Polymerisations
| Autor: | Holder, Simon J. |
|---|---|
| Přispěvatelé: | Holder, Simon J., Street, G., Illsley, Derek R. |
| Jazyk: | angličtina |
| Rok vydání: | 2005 |
| Zdroj: | Polymer Preprints |
| Popis: | RAFT polymerisations of methacrylate monomers at 90°C using 2-phenylprop-2-yl phenyldithioacetate (PPPDTA) as the RAFT agent fail to go to complete monomer conversion. For both methyl methacrylate and butyl methacrylate polymerisations, monomer conversions tended to cease at around 60% after two hours of polymerisation. Kinetic analysis indicated that first-order behaviour was followed in the early stages of polymerisation but deviation occurred in the latter stages. By varying reaction conditions it was ascertained that this effect was not dependent on the structure of the solvent or the monomer:RAFT agent molar ratio. Loss of activity was shown to be incremental with temperature above 60°C for butyl methacrylate polymerisations. 1H NMR and UV-vis spectroscopic analysis of model macro-RAFT agents heated at 90°C in solution suggested that degradation of the active RAFT agent at the terminus of the polymer chain occurred which led to the loss of the propagating radical. |
| Databáze: | OpenAIRE |
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