Adhesive bonding

Question 1

What are the advantages and disadvantages of adhesive bonding?

Answer 1

ADV: sufficient strength for structural applications
non-structural uses (e.g. vibration reduction)
removes localized stresses
DIS: limited temperature ranges
bonding takes a long time
needs high surface preparation
limited reliability

Question 2

Describe the steps of the adhesive bonding process

Answer 2

1) degreasing (oils are removed with soap)
2) sanding
3)cleaning
4)surface treament (increases surface energy)
5) adhesive aplication
6) adhesive curing

Question 3

What is surface energy

Answer 3

the energy of disruption to intermolecular bonds when a surface is create. the more disrupted the bonds the more readily the surface attaches to adhesives

Question 4

how can surface energy be increased?

Answer 4

Mechanical abrasion, laser flame and plasma treamtment

Question 5

What is mechanical interlocking?

Answer 5

Mechanical interlocking occurs as the adhesive flows into the pores on the substrate’s
surface. The interlocking provides a physical impediment to crack propagation at the
interface.

Question 6

What is electrostatic Adhesion?

Answer 6

he charged surface of the adhesive is drawn toward
the oppositely charged substrate, creating a connection.

Question 7

What is diffusion in adhesives?

Answer 7

When a polymer adhesive has polymer chains which entangle and penetrate the chains of the substrate creating mechanical connection

Question 8

What is Chemical Adhesion?

Answer 8

when chemical bonds form between the substraite and the adhesive such as covalent, ionic or hydrogen bonding creating a strong perminant connection

Question 9

What are the design considerations fro adhesives

Answer 9

Adhesives are strongest under shear or compressive forces
larger surface contact increases adhesion