Surprising Temperature Scaling of Viscoelastic Properties in Polymers
| Autor: | V. N. Novikov, Fei Fan, Alexei P. Sokolov, Alexander L. Agapov, Tao Hong |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
chemistry.chemical_classification
Materials science Polymers and Plastics Temperature scaling Molecular mass Organic Chemistry Thermodynamics 02 engineering and technology Polymer 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Viscoelasticity 0104 chemical sciences Inorganic Chemistry chemistry.chemical_compound Viscosity chemistry Materials Chemistry Relaxation (physics) Polystyrene 0210 nano-technology Glass transition |
| Zdroj: | Macromolecules. 51:4874-4881 |
| ISSN: | 1520-5835 0024-9297 |
| DOI: | 10.1021/acs.macromol.8b00454 |
| Popis: | We present detailed studies of segmental dynamics and viscosity in polystyrene (PS) and poly(2-vinylpyridine) (P2VP) with different molecular weights (MW). Analysis reveals that the molecular weight dependence exhibits very different temperature scaling for segmental and chain dynamics: while segmental relaxation in samples with different MW forms a master curve when presented vs T – Tg, the viscosity of the same samples falls on a master curve when presented vs Tg/T (here Tg is the glass transition temperature). This result indicates significant difference in the friction mechanisms for chain and segmental dynamics. Even more puzzling is that the absolute values of viscosity appear to be essentially MW independent when presented vs Tg/T up to surprisingly high molecular weight. In particular, viscosity at Tg does not show any appreciable molecular weight dependence up to MW ≈ 30 000 g/mol. We speculate that molecular scale relaxation (chain dynamics) in polymers behaves similar to the structural relaxati... |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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