The History of glue
Around 200 thousand years ago, during the prehistoric times, the earliest known adhesives were made from bark of birch tree. The earliest confirmed use of animal glue was 4000 years ago. The glue was introduced in Ancient Egypt; it was made from boiling of animal hides, hooves and connective tissue. The glue was rare and expensive; it was used to strengthen the durability of papyrus scrolls and furniture. Ancient people also used glue to waterproof baskets and construct utensils.
Today we have various types of glue and tapes to repair and build anything.
How are Adhesives made today?
Adhesives are made from natural proteins and carbohydrates like dextrin (made out of vegetable starch), casein (the milk protein) and terpenes (found in tree resin). It can be also be made from synthetic molecules.
How does the stickiness work?
Glue needs both adhesive and cohesive bonds.
Adhesive Bonding is the process of joining two surfaces together by applying an intermediate layer to bind two surfaces.
Cohesive Bonding is the process in which glue or tape’s own molecules attract each other and hold it together.
How does stickiness work in glue?
Most glue consists of adhesive polymers.
Glues with two or more components that chemically react instead of just drying have stronger bonds.
Both adhesive and cohesive bonds of glue are strong, but once they dry and later break after drying it can’t be reattached without new glue.
How does stickiness work in tape?
Tape also needs cohesive and adhesive bonds.
When tape is used to attach a broken object it has a weaker bond; if it later breaks again it can be reattached. These weak bonds are called Van der Waals forces. It can only take place when objects are closer than naked eyes can see.
Tape’s one side is coated with a combination of a rubber or rubber like substance and a compound called the tackifier. That is the sticky component.
The tape’s stickiness is determined by:
• The proportion of elastic component and tackifier.
• The thickness of adhesive spread.
• Type of backing material (the side which doesn’t have the adhesive spread)
The adhesive present in tape slides into crack of the surface and then stay in place. This ability is known as viscoelasticity. It then forms Van der Waals forces.
Which is stronger: Glue or Tape?
In terms of the absolute strength of adhesive bonds, glue is stronger. But not all adhesive works well in all circumstances. Glues need enough surface touch to work. Though tape’s bond is weaker than glue it works instantly in an emergency. So, conclude, both are strong and effective in their own ways.