Diffusion in Polyethylene Blends: Constraint Release and Entanglement Dilution
| Autor: | Ernst D. von Meerwall, Nazan Dirama, Wayne L. Mattice |
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| Rok vydání: | 2007 |
| Předmět: |
Alkane
chemistry.chemical_classification Self-diffusion Polymers and Plastics Chemistry Diffusion Organic Chemistry Thermodynamics Quantum entanglement Polyethylene Dilution Inorganic Chemistry chemistry.chemical_compound Volume (thermodynamics) Polymer chemistry Materials Chemistry Dilation (morphology) |
| Zdroj: | Macromolecules. 40:3970-3976 |
| ISSN: | 1520-5835 0024-9297 |
| DOI: | 10.1021/ma070342q |
| Popis: | We have used the 1H pulsed-gradient NMR method to augment our earlier diffusion measurements in n-alkane and polyethylene (PE) melts and blends with measurements in 12 additional melts and in three series of blends at T = 150 °C across the full concentration (c) range. Blends were based on M = 33 kDa PE and contained either n-C50 alkane, M = 1.8 kDa PE, or M = 6.7 kDa PE. The results again agree with our theoretical synthesis involving a smooth transition from Rouse to reptational behavior including constraint release and free volume host effects which depend on T, M, and c. Tube dilation is assumed contained in the constraint-release mechanism; contour length fluctuations are not considered to affect center-of-mass diffusion. The generalized constraint-release term not only reproduces the c and M dependences of both D in fully entangled blends but also mimics or supplants entanglement dilution in blends of PE with (unentangled) n-alkanes n-C50 and n-C12. This approach provides a superior alternative in t... |
| Databáze: | OpenAIRE |
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