Cross-Linking Elmer's Glue With Sodium Borate (Slime Lab)

Cross-Linking Elmer's Glue With Sodium Borate (Slime Lab)

Today in science I learned about monomers, polymers, and cross-linking agents. A monomer is singular part that can be chained to other monomers to form polymers. Polymers are all around us. All plastics are polymers. A cross-linking agent is something that promotes the formation of stronger polymers usually through a chemical reaction. My group and I, (Kira Gedris and Jake Lieberman), did a lab which tested what happens when you mix water and Elmer's glue, the two monomers, with Sodium Borate (or Borax), the cross-linking agent. My hypothesis was that the monomers will react with the borax to form a solid polymer. 

These were the materials needed for the lab:

500 mL water

25 mL Elmer's glue

1 tsp. borax

2 drops food coloring

1 graduated cylinder

1 600 mL beaker

1 250 mL beaker

1 stirring rod

This was the procedure:

1. In the 600 ml beaker, measure 100ml of water

2. Add 1 tablespoon of borax powder to 100 ml of water

2. Measure 25 ml of Elmer's glue in the 250 ml beaker 

4. Measure 5 ml of water and add it to the Elmer's glue 

5. Add 2 drops of food coloring to the Elmer's glue 

6. Gently stir the glue-water solution

3. Measure 40 ml of borax solution with the graduated cylinder

8. Pour the 40 ml of borax in the glue solution 

9. Stir vigorously

10. Dump liquid and runny stuff, remove the polymer from the 250 ml beaker 

11. Observe the polymer

Here is the diagram of the structure of the elmer's glue molecules and the borax molecules and what the structure looks like when you add them together:

Here is a diagram of monomers, (water and glue), added with the cross linking agent, (borate) to create a polymer. Note: The cross-linking agent is circled:

Here is a picture showing the beaker with the polymer solution being mixed:

Here is a picture of the Borax being mixed with water:

Here is a picture of what the polymer looked like: 

These are some of the characteristics of the polymer and the analysis of the data:

Description: smells like glue, feels like a wet deflated balloon, and it's very squishy

Slime Rating(from 1-5, 1 being the least slimy and 5 the most): 5

Slow Poke Test: When the slime was poked slowly, the finger went into the goop easily and then the slime molded around the finger

Quick Poke Test: The finger didn't go through the slime. It glided off to the side of the polymer.

Slow Pull test: The smile pulled apart with ease.

Quick Pull Test: Similar to the slow pull test, the slime separated with ease. 

Blob Test: In this test we were supposed to lay the slime on a flat surface then time it until it flattened out. This test was inaccurate because the slime did not flatten out all the way, but only on the bottom where the table was. 

Bounce Test: The slime was very bouncy and bounced repeatedly after being dropped. 

Other Observations: 

The glue-water solution was pretty constant and thick before we added the borate to it. The glue was thick and clumpy after the borate was added. This is because the cross-linking agent (the borax) cause some of the glue to form a chain and create a strong structure, which was the polymer. 

Elasticity is the tendency of a body to return to its original shape after it has been stretched or compressed. What increases the elasticity of the polymer because it makes the glue more easily changeable, so it can react faster with the borax. 

The slime is viscoelastic because it is both thick and elastic.

Conclusion: 

My hypothesis was supported because if borax is added to the water-glue solution, then it will form the strong polymer slime because monomers create polymers. If we added more borax to the solution, there would be more elasticity because there was more cross-linking agent. Some problems that could have altered our info would be that the mixing of the borax and water wasn't mixed well enough, and that the polymer wasn't stirred right to create the strongest polymer possible. This test will help me in future tests because I will know that weak things, like monomers, can combine to create strong things,like polymers. Also, I will know that by adding the cross-linking agent, the strength of the polymer will increase. An example of where I would use this information would be if I need to create a stronger plastic, I would increase one of the chemicals used to make (specifically the cross-linking agent), and I would have made a stronger polymer. Over all, this lab gave me a greater perspective of what make up certain things, and how I can apply my knowledge of monomers and polymers to real life.

Polymer Scavenger Hunt

Polymer Basics     Name Elizabeth Kresock

Use the sites on the Matter & Atoms page of the Kid Zone at http://sciencespot.net/ to complete this worksheet.

Site #1: HandsOn Plastics
1. Plastics are polymers, which is something made of many units similar to a chain. Each
link in the chain is the “mer” or basic unit usually made out of carbon, hydrogen, oxygen,
and/or silicon.  To make the chain, many links or units are hooked or polymerized together.

2. Many common classes of polymers are composed of hydrocarbons, which contain the elements
carbon and hydrogen. List seven elements that are also found in polymers:Oxygen, chlorine, fluorine, nitrogen, silicon, phosphorous, and sulfur

3. What is one of the most famous silicon-based polymers? Silly Putty
4.  What are the general attributes (properties) of polymers?
A. Polymers can be very resistant to chemicals.
B. Polymers can be both thermal and electrical insulators.
C. Polymers are very light in mass with varying degrees of strength.
D. Polymers can be processed in various ways to produce thin fibers or very intricate parts.

5. What percentage of our trash are plastics? 9.9%

6. What does WTE mean? waste-to-energy. What are two benefits of WTE?
1 – We can use plastics that cannot be recycled.
2 – Incineration of polymers produces heat energy.

Site #2:  History of Plastics
Read the information on this page to help you complete this section. Fill in the blanks with the year it was first
produced and the last name(s) of the person credited with the discovery/development. Use the information to list the
substances with dates from the oldest to the most recent in the box.


Rayon – Developed in 1891 by Bernigaut
Silly Putty - Developed in 1949 by Wright
Cellophane - Discovered in 1900 by Brandenberger
Parkesine - Discovered in 1862 by Parker
Nylon - Developed in 1939 by Carothers
Bakelite - Developed in 1907 by Baekeland
Velcro - Developed in 1957 by Maestral
Saran - Discovered in 1933 by Wiley
PVC (Vinyl) – Developed by Simon
Polyethylene – Developed in 1936 by Fawcett & Gibson
Teflon – Discovered in 1938 by Plunkett
Celluoid - Developed in 1869 by Hyatt


Plastics Timeline
Oldest to Most Recent

1 Parkesine
2 Celluoid
3 Rayon
4 Cellophane
4 Bakellite
5 Saran
6 Polyethylene
8 Teflon
9 Nylon
10 Silly Putty
11 Velcro



Site #3: Nobel Prize.org: Plastics & Polymers
http://nobelprize.org/educational_games/chemistry/plastics/readmore.html


Plastics have changed the world: Where did the word plastic come from?
It came from the Greek word plasticos, which means “to mold,” because plastics are soft and mold-able.

What are plastics?  Synthetic polymers Define the following words after reading the section titled “What are plastics”

• monomer: The building blocks for making polymers
"one part" (mono = one, mer = part)

• polymer: Many monomers that are joined together in chains
"many parts" (poly = many)

• organic material: Carbon Compounds

Polymerization: The steps listed below explain how plastic is made. Fill in the missing blanks.

1. Crude oil, the unprocessed oil that comes out of the ground, contains hundreds of different hydrocarbons, as well as small amounts of other materials. The job of an

oil refinery is to separate these materials and also to break down (or "crack) large hydrocarbons into smaller ones.

2. A petrochemical plant receives refined oil containing the small monomers they need and creates polymers through chemical reactions.

3. A plastics factory buys the end products of a petrochemical plant - polymers in the form of resins - introduces additives to modify or obtain desirable properties, then molds or otherwise forms the final plastic products

Polymers are Everywhere: Read the paragraph titled “Polymers are Everywhere”, then answer true or false to the following questions.

• True Plastics are polymers, but polymers don't have to be plastics.

• False Cellulose, the basic component of plant cell wall, and DNA, the long molecule in the nuclei of your cells that carries all the genetic information about you, are both examples of plastics.

• True Natural polymers include silk, wool, cotton, wood, and leather.

Thermoplastics & Thermosets: Plastics are classified into two categories according to what happens to them when they're heated to high temperatures. Complete the table below.

Thermoplastics Thermosets

Can it be shaped?	yes	no
Analogy	When ice is heated, it melts. When thermoplastics are heated, they melt.	Just like a raw egg can become a boiled egg, a scrambled egg, etc; a thermoset can become many different things.
Strong or weak bonds	weak, connected, linear, bonds	strong, cross-linked bonds
Uses	There are many different uses including food wrap, food containers, lighting panels, and garden hoses.	Thermosets are used for things that can be heated up such as kitchen spatulas, and other kitchen tools. They are also in glues and circuitboards.
Recyling: Easy or Hard?	Easy because they can be molded into different shapes.	Hard because they have to be crushed to create powder which can be used for other thermosets.

Site #4 – Polymer Flash Activities

1. Click the link to make a virtual polymer and choose polyethylene.
A. What type of monomer is used to make this polymer? Ethylene
B. What elements and how many of each is in one of these monomers?
 C = Carbon  # - 2  H = Hydrogen  # - 4
C. What starts the process? Initiator

2. Click the link to try the matching games.  Record your times or scores in the blanks below.
A. Breakfast Game– 1st Try = 9588   2nd Try = 9632  3rd Try = 9608
B. Polymer Game - – 1st Try = 9615   2nd Try = 9621  3rd Try = 9379