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Presentation about polydispersity and Molecular weight distribution in polymers
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- 2. Submitted to: Dr.Mihir lalBhowmik Associate Professor Department of chemistry Comilla University Submitted by: Nilufa yeasmin Rikta ID:11914027 Session:2018-19 Department of chemistry Comilla University
- 3. Presentation on: Polydispersity andMolecular weight distribution in polymer.
- 4. What does Polydispersitymean? Polydispersity is a measure of the distribution of molecular masses in a polymer sample. It is the ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn) of the polymer. Mathematically, it is expressed as: Polydispersity = Mw / Mn
- 5. A polydispersityvalue of 1 indicates a perfectly monodisperse polymer, where all the polymer chains have the same molecular weight. Values greater than 1 indicate a distribution of molecular weights, with higher values representing a broader distribution. Polydispersity is an important parameter in understanding the properties and behavior of polymers, as the molecular weight distribution can significantly impact a polymer's physical, mechanical, and processing characteristics.
- 6. Monodisperse polymer • Monodispersepolymers are macromolecular materials having a precise and discrete Molecular weight. • Uniform • Consistent shape and mass distribution • Single Molecular weight value Polydisperse polymer • Polydisperse polymer are macromolecular materials having a rang of components with a range of Molecular weights • Non –uniform • Inconsistent shape,size and mass distribution • A range of values for Molecular weight
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- 8. Polydispersity gives anidea of the lowest and highest Molecular weight species as well as the distribution pattern of the immediate Molecular species. Polydispersity
- 9. Molecular weight distribution It May be recalled that a simple chemical compounds contains molecules, each of which has the same Molecular weight (a monodispersed),whereas a polymer contains molecules, each of which can have different Molecular weights(polydisperse system).
- 10. Molecular weight distribution Thisfigure shows Molecular weight distribution in two samples having same number average Molecular weight but different polydispersity. Sample 1 obviously has narrower dispersion pattern and hence a lower polydispersity than sample 2.
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