Polymer Lab

Cross-linking Elmer's glue with sodium borate

The problem is, what is the change in physical properties of a polymer as the result of a cross-linking? How does adding more agents change it? and if we cross-link the Elmer's glue with the sodium borate, then it will change the state of matter and the more sodium borate that is added, the bigger the change.

The materials that will need to be used for this lab are: 500mL of water, 25mL of Elmer's glue, 1 tsp. of borax, 2 drops of food coloring, 1 graduated cylinder, 600mL beaker, 250mL beaker, and a stirring rod. 

The procedures are to add one tablespoon of borax and 100mL of water to the 600mL beaker, then stir. Squeeze 25mL of Elmer's glue and 5mL of water to the 250mL beaker then carefully stir the solution. Now mix the borax and the glue solution together. Now stir quickly while the solution takes place. And if there is excess liquid, pour it out, into the sink.

After the stirring was over, we removed the slime from the beaker and conducted a series of evens. The slime test results were that it was very slimy, smelled like glue, very squishy, in a way looked like egg whites. On a scale from 1-5 its sliminess was about 4. It was very lob-sided and highly bouncy. We did a quick and slow poling test of the slime and it just broke apart on each one when there was pressure applied. On the slow poke test it did not really penetrate through the slime. But on the quick poke test, my finger went completely through the slime and poked out the other side. 

In the end, my hypothesis was proven correct, because the state of matter was in fact change, because it went from a liquid substance, into almost a solid. And this occurred, because the two substances were cross-linked, and thus created the slime product. And a polymer was formed, due to that all of the sodium borate and glue's monomer all connected into a linked chain that created this in between substance thats almost a liquid and a solid at the same time.

1. How is slime visco-elastic?
It is visco-elastic, because the its definition is to be deformed when pressure is applied, and once it has been released, it returned back to it almost original shape.

2. What are the physical properties properties that change as a result of the addition of sodium borate to the Elmer's glue?
Well it changed pretty dramatically, because after stirring the glue and the water the glue seemed as if it wasn't sticking to anything, so it basically just a liquid. The sodium borate was mixed with water as well so it was to liquid coming together to make this polymer. Once the slime was created it was large in size and it was in a ball, so it turned into a polymer.


3. What would be the effect of adding more sodium borate to your cup? (your thoughts only)
I definitely believe that the slime would be bigger in size and it would be more slimy, because of the water and sodium borate that is in the mixture, so if there was to be more added, it would change.


4. After making the observation of the dried glue, how does the water affect the elasticity of the polymer? What is elasticity?
I think that water affects the elasticity, because when the water is added to the Elmer's glue, all of the monomers are in the and once it is added it pushes them together into a chain, creating a polymer. And elasticity is the ability to stretch something when force is applied, but when that force/pressure is released, it will return to its original state.