Effects of Attractive Forces on Polymer Rubber Stress-Strain Curve

In summary, the average separation of the chain ends of a freely orienting chain with 1000 segments each of length 7 AO subjected to a force on its ends of 10-5 N would be 70 cm. The force required to elongate a piece of polymer with an original length of 10 cm, an area of cross section of 0.1 cm2, Mn = 30,000, Mc = 6000, and density of 0.90 gm/cc to a length of 2.54 cm would be 7.5 N. The attractive forces between chains in a polymer that decreases as the chains are oriented would reduce the yield point of the equilibrium stress-strain curve for that polymer rubber.
  • #1
nooon
1
0
1. Suppose a freely orienting chain with 1000 segments each of length 7 AO is subjected to a force on its ends of 10-5 N. What will be the average separation of the chain ends?
2. How large a force is needed to elongate the following piece of polymer to a length of 2.54 cm?
Original length = 10 cm.
Area of cross section = 0.1 cm2
Mn = 30,000, Mc = 6000
Density = 0.90 gm/cc
3. Consider a polymer for which the potential energy resulting from attractive forces between the chains decreases markedly as the chains are oriented. What can one say about the effect of these forces upon the equilibrium stress-strain curve for that polymer rubber?
 
Physics news on Phys.org
  • #2
Answer: 1. The average separation of the chain ends would be 70 cm. 2. The force required to elongate the piece of polymer to a length of 2.54 cm would be 7.5 N. 3. The effect of the attractive forces between the chains on the equilibrium stress-strain curve for that polymer rubber would be to reduce the yield point, or the point at which the material begins to deform plastically. This is because the attractive forces will cause the polymer chains to align, reducing the energy required for deformation.
 

Related to Effects of Attractive Forces on Polymer Rubber Stress-Strain Curve

1. How do attractive forces affect the stress-strain curve of polymer rubber?

Attractive forces, such as hydrogen bonding and Van der Waals forces, play a crucial role in the behavior of polymer rubber under stress. These forces act as intermolecular bonds between polymer chains, causing them to resist deformation and resulting in a more gradual stress-strain curve.

2. What is the difference between the stress-strain curve of a polymer rubber with and without attractive forces?

Without attractive forces, the stress-strain curve of polymer rubber would be steeper and show a more sudden increase in stress with strain. This is because without intermolecular bonds, the polymer chains would easily slide past each other, resulting in a less resistant material.

3. Can attractive forces affect the elasticity of polymer rubber?

Yes, attractive forces can affect the elasticity of polymer rubber. The presence of these forces allows the polymer chains to stretch and deform more easily, resulting in a more elastic material. However, excessive attractive forces can also cause the polymer chains to become too rigid, decreasing elasticity.

4. How do temperature and pressure impact the effects of attractive forces on the stress-strain curve of polymer rubber?

Temperature and pressure can significantly influence the behavior of attractive forces on the stress-strain curve of polymer rubber. As temperature increases, the intermolecular bonds weaken, resulting in a decrease in the resistance to deformation and a steeper stress-strain curve. On the other hand, high pressure can strengthen these forces, making the material more resistant to deformation.

5. What other factors can affect the effects of attractive forces on the stress-strain curve of polymer rubber?

Apart from temperature and pressure, factors such as the molecular weight, chain length, and degree of cross-linking can also impact the effects of attractive forces on the stress-strain curve of polymer rubber. Higher molecular weight and longer chain length tend to increase the strength of intermolecular bonds, while cross-linking can either strengthen or weaken these forces depending on the type and amount of cross-links present.

Similar threads

Deformation of a metal sheet with a tip force applied
    • Introductory Physics Homework Help
Replies
5
Views
1K
Stress strain diagram of mild steel -- gauge length made half
    • Mechanical Engineering
Replies
1
Views
1K
Solve 2 Problems: Help with 500 N Force & Elongation of Aluminum Wire
    • Introductory Physics Homework Help
Replies
13
Views
5K

Hot Threads

Recent Insights

Back
Top