Understanding of the adhesive (glue) and understanding of adhesion (adhesion), and also an understanding of adhesion failure becomes very important. For that there are several theories that need to be understood, d iantaranya are: Surface Tension (Surface Tension) to bind through a material, the adhesive must be able to wet and spread over the surface of the material well. Thus the factor of surface tension (surface tension) of the material to be glued and the adhesive to be very influential.
This means that the surface tension of the glue must be smaller than the surface tension of the material.
(1) Physical Adsorption
The appeal of the two kinds of objects or substances called physical adsorption. The appeal is also called Style Van Der Walls. In addition, there is another attraction that is caused by the dispersion forces. The appeal is contained in all the molecules of the object or substance.
Dispersion forces are dipole (positive and negative electrical charges) generated by the movement of electrons in the molecule. The appeal of this (style of Van Der Walls and style Dispersion) sufficient to produce a bond or bondingdari two objects or substances. In this case the glue layer and the object to be glued.
(2) Hydrogen Association
A substance that molecules containing hydroxyl group can create a bond with the molecules of other substances through hydrogen bonds. Examples of materials that have a hydroxyl group (- OH) are starch and dextrin.
(3) Adsorption In Chemistry
A substance that molecules containing an active group of atoms, can bind to molecules of other substances by chemical bonds. This bonding also called chemical adsorption (chemisorption). This bonding produces an adhesiveness (bonding) are durable.
The bond between the substance A / B with a layer of glue can occur due to physical adsorption (weak); hydrogen bonds (strong enough); and chemical adsorption (strong). After the substance A and B (which has been coated with adhesive) are glued, then the bonding that occurs on the surface that has been coated with glue dispersion is caused by the force of the molecules of the glue itself.
Advantages of Using materials Adhesives
Gluing or gluing has several advantages compared with traditional means such as nails, screws, and others. Some advantages of using adhesives are as follows:
(1) to glue the thin material to other materials without causing damage to the material.
(2) The shape of the end product more smoothly because there is no gap, bulge nails, screws, and others.
(3) The results of adhesion is more resistant to vibration and expansion, d isebabkan by temperatu r or humidity changes.
(4) The process is faster and more economical.
Adhesion Failure Causes
The causes of failure gluing or gluing is as follows:
- Using adhesive (glue) that do not fit
- Work on the material surface is not perfect
- Influence of water
- The influence of stress (stress)
- The influence of corrosion (corrosion)
- Effect of heat
- Not fulfilled the conditions or procedures of the way of gluing.