Effect of cross-linking/fillers on relaxation time

[generous]

Hello all

I'm glad to join the forums and having the opportunity of having some scientific discussions

I'd like to discuss with you the effect of cross-linking or adding fillers to the relaxation of a polymer

I believe that they have the same effect..as both lead to the restriction of the chain mobility

but the question is...as a result, does the relaxation time increase or decrease?

restricting the chain mobility means that there will be no motion and consequently the relaxation time decrease? or it means that the motion will take place but at longer time scales..so the relaxation time increases?

I appreciate your help as it is really confusing for me

 

[Chestermiller]

If more and more cross links were added, the relaxation time would have to decrease.

 

[generous]

thanks for your answer..but can you clarify why?

 

[Chestermiller]

thanks for your answer..but can you clarify why?

It would make the structure stiffer by shortening the segments between cross links.

 

[alphy]

I can provide some insight into the effect of cross-linking and fillers on relaxation time in polymers.

Firstly, let's define what relaxation time is in this context. It is the time required for a polymer chain to return to its original configuration after being stretched or deformed. This time is influenced by various factors such as temperature, molecular weight, and the presence of cross-linking and fillers.

Cross-linking refers to the formation of chemical bonds between polymer chains, which restricts their mobility and increases the mechanical strength of the polymer. This can lead to a decrease in relaxation time as the polymer chains are less able to move and return to their original state. However, this effect may be more significant at lower temperatures, where the polymer chains have less thermal energy to overcome the cross-links.

On the other hand, adding fillers such as nanoparticles or fibers can also affect relaxation time. These fillers can physically hinder the movement of polymer chains, leading to a decrease in relaxation time. However, they can also increase the mechanical strength of the polymer and improve its resistance to deformation, which may lead to a longer relaxation time.

Overall, the effect of cross-linking and fillers on relaxation time can vary depending on the specific polymer system and conditions. It is important to consider all factors and conduct experiments to determine the precise effect on relaxation time. I hope this helps clarify some of the confusion and sparks further discussion on this topic.