Thermal stability of RAFT-based poly(methyl methacrylate): A kinetic study of the dithiobenzoate and trithiocarbonate end-group effect
| Autor: | Anastasija D. Jablanovic, Marianna Z. Bekanova, A. V. Plutalova, Nikolay K. Neumolotov, Yaroslav V. Kudryavtsev, Elena V. Chernikova |
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| Rok vydání: | 2019 |
| Předmět: |
Molar mass
Polymers and Plastics technology industry and agriculture Chain transfer macromolecular substances 02 engineering and technology Raft 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Poly(methyl methacrylate) 0104 chemical sciences End-group chemistry.chemical_compound chemistry Polymerization Mechanics of Materials visual_art Polymer chemistry Materials Chemistry visual_art.visual_art_medium Thermal stability Methyl methacrylate 0210 nano-technology |
| Zdroj: | Polymer Degradation and Stability. 164:18-27 |
| ISSN: | 0141-3910 |
| Popis: | Thermal stability of dithiobenzoate- (DB) and trithiocarbonate- (TC) terminated poly(methyl methacrylate) (PMMA) synthesized via reversible addition–fragmentation chain transfer (RAFT) polymerization is systematically studied under dynamic heating and prolonged isothermal treatment at 100–180 °C. It is demonstrated that in the presence of functional end-groups the onset of mass loss can be shifted relative to conventional PMMA, either toward higher (PMMA-DB) or lower (PMMA-TC) temperatures. Irrespective of the polymer molar mass, a loss of PMMA chain-end functionality clearly manifests itself upon 24 h of isothermal treatment at 120 °C for DB end-groups and already at 100 °C for TC ones. At 120 °C (for PMMA-TC) and 140 °C (for PMMA-DB) the ability of both polymers to serve as macromolecular RAFT agents in the chain extension processes ceases almost completely. The kinetics of functional end-groups elimination depends on their chemical nature. In the case of DB-groups, the reaction is of the first order, whereas TC-groups containing two C S bonds demonstrate more complex degradation kinetics. We propose a two-step mechanism of TC-group elimination, which enables interpretation of the observed experimental data. |
| Databáze: | OpenAIRE |
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