Intrinsic viscosity of a polymer and its density

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SUMMARY

The discussion centers on the relationship between intrinsic viscosity (IV) and density in polymers. Two polymers in pellet form are compared, revealing that while higher intrinsic viscosity typically correlates with higher molecular weight and melt viscosity, it does not guarantee higher density. The participants clarify that viscosity and density are independent properties, with examples illustrating that substances can have high viscosity but lower density, such as motor oil compared to water. The intrinsic viscosity is defined as a measure of a solute's contribution to the viscosity of a solution, although the user is melting the polymers rather than dissolving them.

PREREQUISITES
  • Understanding of intrinsic viscosity (IV) and its significance in polymer science
  • Knowledge of polymer properties, including molecular weight and melt viscosity
  • Familiarity with the definitions of viscosity types: dynamic, intrinsic, and inherent
  • Basic concepts of fluid properties, particularly the independence of viscosity and density
NEXT STEPS
  • Research the relationship between intrinsic viscosity and molecular weight in polymers
  • Explore methods for measuring melt viscosity in polymer samples
  • Investigate the effects of temperature on the viscosity and density of polymers
  • Learn about the different types of viscosity and their applications in material science
USEFUL FOR

This discussion is beneficial for polymer scientists, materials engineers, and anyone involved in the study or application of polymer properties, particularly those interested in viscosity and density relationships.

fog37
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Hello Forum,

I have two polymers (both in pellet form). Their spec sheet shows that the two polymers have different intrinsic viscosity IV. There are so many definitions of viscosity (dynamic, intrinsic, inherent, etc.)

In general viscosity and density are two independent properties of a fluid. Surely most common substances that have high viscosity also have high density.Regardless, it seems that the two properties are not connected. One example: Some motor oil is more viscous than water but less
dense than water.

As far as IV (intrinsic viscosity): http://en.wikipedia.org/wiki/Intrinsic_viscosity
it is defined as s a measure of a solute's contribution to the viscosity of a solution...

I would like to understand if the polymer rated with larger IV also has a higher density than the other one. I am simply melting the polymers and not putting them into a solution with a solvent...

Thanks,
Fog37
 
Chemistry news on Phys.org
Higher iv correlates with higher molecular weight. This them correlates with higher melt viscosity. Iv is usually used to compare molecular weights for the same polymer.

Chet
 
Thank you Chet
 

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