What is Glue?
Glue is the sticky liquid substance that we use to make fun crafty projects and repair the things we ought not to have broken. Every object has dents and gaps on its surface, on where the glue seeps in and settles down. When exposed to air, this liquid hardens to form a solid that securely attaches the two objects. There are innumerous types of glue that are available in the market; and now glue is made non toxic so that it does not harm the little kids who might accidentally put it in their mouths. But what is glue made from my curious mind asks?
How was it made?
Traditionally glue was made from animal products like the skin and bones. The bones are first boiled and the fat is separated. Further cleaning and boiling leads to the animal matter or the collagen protein being transformed into gelatin. This is dried and made into a cake; and boiled in hot water before use. This glue was used to make Egyptian caskets for the pharaohs, wooden furniture in the Roman Empire, violin making in the 16th century, book binding in the 19th century and today it is used in making medicine capsules. Tar and beeswax was also combined to form glue. Egg whites, acacia gum and honey was mixed to form special glue that was used in making musical instruments.
From where is it extracted?
Glue is also extracted from trees. The Red Manjack Tree which is found in India gives fruit to red berries which look like tomatoes; which contain the edible and sticky glue that is commercially used today.
Casein glue derived from the Latin word meaning cheese; is hydrophobic and is made from milk products. You can try making this glue at home. When you add vinegar to hot milk, the milk separates into whey and curd. If you add hot water and baking soda to the curd and dissolve it; you will have the glutinous substance called glue.
Starch is the carbohydrate that is found in trees, potatoes, wheat etc. Potatoes are smashed and the starch is derived from the dead potato cells. Low gooey temperature and high stickiness make it a sister of glue. The glycerin is mixed to make it thicker. Starchy glue is commercially very popular and safe to use.
The Discovery of Glue
- Charles Goodyear experimented and discovered that when rubber is heated with sulfur; it forms glue. This is used in the automobile industry.
- Dr Harry Coover discovered the glue substance called cyanaocrylate which was later formulated to make the popular Krazy glue.
What is Glue made of Today?
Hot glue is made of thermoplastics that are heated and used for effective sticking between various materials. This type of glue is liquid and hardens on cooling and thus forms a strong adhesive.
Today thermoplastic glue is more efficient and effective in moist and humid climates; where other glues dissolve and loosen the materials bound together.
But the best way to make glue is at home. Mix one cup of flour, 1 ½ cups of water, 1/3 cup of sugar and 1 tsp of vinegar together. Heat it slowly and when the mixture becomes thick, store it in an air tight container and use it when cooled. This will keep the little babies busy for hours.
Today different types of glue are made for different applications. You will find paper glue, wood glue etc. Everything leads to being more constructive and creative.
3 Interesting Facts about Glue
- The first recipe of glue was written in 2000 BC.
- The 5200 year old Iceman found in Austria, in a glacier; was seen with axes which were bound together with glue called pitch.
- The first US stamps were adhered on mailing envelopes with starch glue in 1840.