Adhesive Bonding Flashcards
1
Q
Mechanical interlocking theory
A
The adhesives displaces air in pores and cavities, and hardens
2
Q
Electrostatic/electronic theory
A
Adhesive and forces are stuck to each other by electrostatic force- resistant to removal
3
Q
Diffusion theory
A
INTERDIFFUSION OF MOLECULES IN AND BETWEEN THE ADHESIVE AND ADHEREND. Applicable when both are made of long-chain molecules capable of movement
4
Q
chemical Bonding theory
A
literal chemical bonding between the surfaces and adhesives, e.g. hydrogen bonding
5
Q
What is the definition of surface energy
A
Energy required per unit area to increase size of surface. For adhesives, we generally prefer high surface energies, as it’ll get into all the small cracks and shit
6
Q
Advantages of adhesive bonding
A
- can be used for insulation and vibration absorption
- Distributes load, and decreases localized stress
- structural integrity of sections maintained
- External appearance unaffected
- Thin and fragile components can be bonded without increasing weight significantly
- Porous materials of very different properties and sizes can be joined
- Usually set at room temp, so no significant distrotion in components
7
Q
Limitations of adhesive bonding
A
- Limited range of service temperatures
- relatively long bonding time
- Great need for surface preparations
- Bonded joints are difficult to test for non-destructibility, especially for large structures
- Limited reliability and lifetime under hostile environmental conditions
