Equation for number of crosslinked polymer strand in rubber

  • Thread starter semc
  • Start date
346
2
I am doing an experiment to estimate N, the number of crosslinked polymer strand in a piece of rectangular rubber. To do this, I attached weights to the rubber and measure the extension of the rubber when subject to the force. However, I found two equations that can be used to find N and they give different results hopefully someone can tell me which equation I should use.

Firstly, [tex]F=N(kb)T(\frac{x+X}{X^2}-\frac{X}{(X+x)^2})[/tex] where (kb) is the boltzmann constant, T the temperature, X is the original length and x is the total length of the rubber after the weight is added.

The second equation is k=(3NkbT)/X2 where k is the spring constant of the spring. I have totally no clue where this equation is derived from.

Thanks
 

Want to reply to this thread?

"Equation for number of crosslinked polymer strand in rubber" You must log in or register to reply here.

Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving

Top Threads

Top