Lecture 4: Coupling Agents

Question 1

How is compatibilizer different from coupling agents?

Answer 1

Compatibilizer makes two polymers compatible with one another, while coupling agents make matrix to fiber adhesion and interaction optimized. So that when load is transferred from matrix to fiber, the composite can handle the force.

Question 2

Why CMCs and MMCs not need coupling agents?

Answer 2

Because they have similar bonding already from the fiber to the matrix. Polymer matrices on the other hand have different.

Question 3

What are the four mechanisms by which fibers and matrices adhere to one another?

Answer 3

1. Adsorption by wetting
2. Electrostatic interaction
3. Chemical bonding
4. Mechanical adhesion

Question 4

Coupling agents may be added to the resin, fiber, or both. What is their role?

Answer 4

Agent acts as interface between resin and glass fiber (or mineral filler) to form a chemical bridge between the t

Question 5

What are the most commonly used coupling agents?

Answer 5

1. Silanes
2. Titanates
3. Organometallics surfactants

Question 6

What is the structure of silanes?

Answer 6

Y-Si(OR)3

Question 7

Silanes have the ability to bond inorganic materials such as glass, mineral fillers, metals and metallic oxides to organic resins. True or false?

Answer 7

True

Question 8

In the structure Y-Si(OR)3, which part interacts with the fiber and the polymer? What does this do to the glass fiber’s properties?

Answer 8

Y -> polymer
OH/OR -> fiber

Hydrophilic glass becomes hydrophobic.

Question 9

What are the main benefits of using silane as the coupling agent?

Answer 9

1. Improving wet-out of the mineral by the polymer
2. Durability in Wet Environment
3. Better Mechanical properties
4. Retention of Electrical Properties
   5.

Question 10

For PMCs in he use of hot and