Types of Glue – Glue Tips

Nowadays, glue is a necessity to all of the students, teachers, and some office workers every day. Milk contains casein, a protein that is used in the production of glues, paints and plastics, as well as some food products. If you heat up milk and add an acid, such as vinegar, you will cause a chemical reaction whereby the casein separates from the liquid component of milk. When you add a base, such as baking soda, to the casein extracted from milk, the acid is neutralized and the result is a smooth adhesive that can be used for wood and paper.

Glue is the main topic in this investigatory project. Glue is widely used worldwide. From schools to offices, from homes to buildings, glue is always used by individuals in their daily lives. This material can be used in simple works or as an emergency utensil; from torn books to stripped parts of paper works; this tool is very significant in our lives. (Cruz, 2015)

Glue is a sticky material that can stick two or more things together. Glue can be made from plant or animal parts, or it can be made from oil-based chemicals. The first glues may have been natural liquids that come out of trees when they are cut. As technology progress, people learned to make glue by boiling animal feet, cartilage or bones. Some very strong glue is made from fish bones, rubber or milk. Simple glue can be made at home by mixing wheat flour and water. This glue will stick pieces of paper together. Many kinds of art can be made using glue. A collage is a work of art made by using glue to stick colored things onto paper.

Casein, a protein obtained from milk, has been long proven to play an important role in the production of glue. It can be obtained from milk by means of adding vinegar in to the milk. The curd formed from the reaction is mixed with baking soda. The produced glue from milk may vary in consistency depending upon the amount of milk, vinegar, water and baking soda used. Other research conducted claims that glue made from milk casein is waterproof and can be used for bottle labeling and cigarette packaging. (Papica, 2013)

Some variants of glue can be used to keep water out of boats, buildings or vehicles. In this case the glue may be called caulk. Some man-made materials, including wood-like materials, are made using glues to bind together small pieces of material or powders. These qualities of our project, the homemade glue, really come in handy to our fellows with problems about toxics in their homes. This project isn’t only helpful to us, but is also easy to organize in times of need and emergencies.

Statement of the Problem
This study seeks to answer the following answers:
1. Is it effective?
2. Are the ingredients easy to find?
3. Is it eco-friendly?
4. Is it convenient to use?

Statement of the Hypothesis

The researchers learned that the homemade glue from milk is effective. The ingredients can easily found and is eco-friendly, since most of it is used in the house. The glue is also convenient to use since it is a lot cheaper and has accurate results.

Significance of the Study
The researchers discovered useful home materials that can replace glue. Glue is one of the most common things usually used by the students, whether in projects or simple home repairs. Sometimes, we could not avoid the fact that the milk in our refrigerators get sour.
This project aims to develop glue that will benefit the students, teachers, office workers and other people who use glue in their works.
The people who are going to benefit from this homemade glue are the following:

First, Students need glue to stick our test results in our notebooks. Students also need it for creating arts and other creative materials.
Second, is the people who works in the office might need glue because they use it as the paste their finished product to be submitted to their boss.
Third, are the teachers, they will need in order to paste the students test result in the notebook.

Definition of Terms
The following terms are frequently used in our research. These terms are defined according to their use in this research.
Milk
Milk is a whitish liquid containing proteins, fats, lactose, and various vitamins and minerals that is produced by the mammary glands of all mature female mammals after they have given birth and serves as nourishment for their young.
Casein
Casein is a white, tasteless, odorless protein precipitated from milk by rennin. It is the basis of cheese and is used to make plastics, adhesives, paints, and foods.
Glue
Glue is a hard, impure, protein gelatin, obtained by boiling skins, hoofs, and other animal substances in water, which when melted or diluted is a strong adhesive.

Milk is something that comes from mammals. It can also be seen in sachet packs and bottles. It is rich in calcium and sold in markets as pure, evaporated, condensed, low-fat and skimmed milk. It has pH level ranging from 6.7 to 6.5. But in this research, the researchers, discovered and learned about the two parts of milk—the curd and the whey. The whey is the watery part of the milk. It is the one left behind after the milk curdles. The curd is the solid part that forms during milk curdling. They are milk proteins; called casein. Liquid casein is natural glue. Skimmed milk can make more curds because its cream and fat has already been removed. The fat protects the proteins in the milk especially casein. People can deliberately curdle milk by using any edible acidic substances like vinegar. The major protein in milk is casein.

This protein is very susceptible to chemical changes when in solution. An example of this would be adding acid to milk and then it curdles (casein proteins are clumping together). At lower pH (4.6 for casein) the charge on the protein becomes neutral. At any other pH, the proteins are all charged. Since like charges repel, only when there is no charge (at 4.6, this is called the isoelectric point) will the proteins be able to come together and clump. Vinegar, one of the most important condiments in our kitchens, consists mainly of acetic acid (CH3 COOH) and water. It has pH levels ranging from 2.3 to 3.3.

Since it is acidic, it reduces the pH levels of any substance it mixes with. It causes the casein proteins of milk to form lumps. Baking soda or sodium bicarbonate (NaHCO3) neutralizes the vinegar. In water, baking soda breaks apart into a positively-charged sodium ion (Na+) and a negatively charged bicarbonate ion (HCO3-).
In the early 1900s until about 1945, plastic made from milk was quite common. This plastic, known as casein plastic, was used to manufacture buttons, decorative buckles, beads, and other jewelry, as well as fountain pens and hand-held mirrors and fancy comb-and-brush sets. The results show that the best recipe for making plastic out of milk is adding the eight teaspoons of vinegar to one cup of milk heated to 49 degrees Celsius. (Evans, 2014)

It was estimated that every person used about 40 lbs. of adhesives especially glue each year. Glue was mainly used in making crafts, furniture, plumbing, shoes, books, buildings and a lot more. Many commercial glues can be bought anywhere, but there are also alternative household materials that can be used in making an adhesive. These materials are the most common of all: flour, milk, water, sugar, vinegar and baking soda(Naïve,2012)

Milk can be transformed into curds and whey by adding (1) rennet or (2) a mild acid such as acetic acid. Since vinegar is acetic acid, it is used in this experiment instead of more expensive reagent grade materials. After curds form and are separated from the whey, the acid is neutralized with the sodium bicarbonate. The clumps of curds are comprised of casein, a protein found in milk. Casein proteins make up 3% of whole milk. Glues made from casein include products such as Elmer’s and other woodworking glues. Casein can also be poured into molded into forms to making a variety of plastic items such as combs, bead, button and umbrella handles. (Webb,2014)

Experiments that created glue from milk, vinegar, baking soda, and water resulted to effective adhesion of the formed glue. By adding vinegar to the milk, a chemical reaction is created which makes the milk separate into two parts: curds and liquid (whey). The curds are milk protein, called casein. Liquid casein is natural glue.
When baking soda is added, it neutralizes the vinegar, which is acidic. The bubbles that are formed and given off after the reaction are carbon dioxide. The curds form liquid again after being neutralized. (Vanstone, 2012)

Van der Waals forces explain how the lizards known as geckos can stick to so many surfaces in a seemingly impossible manner. The tiny hairs on the gecko\’s feet (called setae) are split at the microscopic level into \”as many as 1,000 branches, whose spatula-shaped tips are only 200 nanometers wide.\” As a result, even though the Van der Waals forces acting on an individual tip is small, the adhesion of a billion or so tips adds up to enough force to let the gecko stick to anything. (Ben-Ari, 2014)

A good glue has excellent properties of adhesion (the ability to stick to the surfaces to which it\’s applied) and cohesion (the ability to stick to itself). When you pull apart something that\’s been glued together and the glue comes right off the pieces, that\’s an adhesive failure. If the glue itself splits apart, leaving glue on either side of the joint, then that\’s a cohesive failure. Adhesion and cohesion are both important for a glue to work. (Cruz,2015)

A polymer is a large molecule that often is described as being a long molecular strand, much like spaghetti. Some polymers are naturally \”sticky\” depending on how they are made. Others require certain ingredients called tackifiers to make them sticky. The hard part for glue makers is to find the right balance of polymers and tackifiers to make a glue that is both sticky and strong. Glue doesn’t however stick to the inside of the bottle. This is because as long as it stays in the bottle, air can’t get to it and the glue remains a fluid. Glue hardens when there is a loss of water from the mixture. Exposing the glue to air makes the water evaporate and the glue hardens. (Webb, 2014)

How can milk be changed into plastic? To answer that we need to think first about what plastic is. The word plastic is used to describe a material that can be molded into many shapes. Plastics do not all look or feel the same. Think of a plastic grocery bag, a plastic doll or action figure, a plastic lunch box, and a disposable plastic water bottle. They are all made of plastic, but they look and feel different.

Why? Their similarities and differences come from the molecules that they, like everything else, are made of. Molecules are the smallest units (way too small to see with your eye!) of any given thing. Plastics are similar because they are all made up of molecules that are repeated over and over again in a chain. These are called polymers, and all plastics are polymers. Sometimes polymers are chains of just one type of molecule. In other cases polymers are chains of different types of molecules as in the bottom half that link together in a regular pattern. A single repeat of the pattern of molecules in a polymer “even if the polymer uses only one type of molecule” is called a monomer. (Castor, 2013)

The 80 percent of protein in cow milk is a substance called casein, which already finds uses in making adhesives and paper coatings. But casein is not very strong, and water can wash it away. To beef up casein, and boost its resistance to water, the scientists blended in a small amount of clay and a reactive molecule called glyceraldehyde, which links casein’s protein molecules together. The scientists freeze-dried the resulting mixture, removing the water to produce a spongy aerogel, one of a family of substances so light and airy that they have been termed “solid smoke.” To make the gossamer foam stronger, they cured it in an oven, then tested its sturdiness. They concluded that it is strong enough for commercial uses, and biodegradable, with almost a third of the material breaking down within 30 days. (Schiraldi, 2013)

If we are able to create plastic with all different types of milk, the result will be the same because all of them contain the same amount of proteins, and that\’s the key of our project. The difference between the different types of milk is the amount of lipids, and this doesn\’t affect the formation of plastic. The proteins, which are the same in all types of milk, are what we need to create plastic. (Platel, 2012)

References:
https://prezi.com/7mui0bxs6svi/turn-milk-into-plastic/
https://prezi.com/ntoizk-x7uon/turning-milk-into-plastic/
https://www.scientificamerican.com/article/bring-science-home-milk-plastic/
https://www.acs.org/content/acs/en/pressroom/presspacs/2010/acs-presspac-november-17-2010/biodegradable-foam-plastic-substitute-made-from-milk-protein-and-cla.html
https://www.academia.edu/9988703/Moo_Glue?auto=download