How did the viscosity change as a greater amount of borax solution was added?
The material becomes more viscous as we mix the PVA and the borax. It will reach a maximum level of viscosity and will not thicken further without more cross-linking agent. The addition of a higher ratio of Borax will result in a very viscous polymer (like Jell-O).
Why does addition of borax to the polyvinyl alcohol affect its physical properties?
In this experiment, a polymer (polyvinyl alcohol) chemically reacts with borax to form a crosslinked polymer network. Individual polymer chains are formed by covalent bonds, which are strong bonds. However, even though this crosslinking is weak, it does alter the properties of the resulting polymer.
What does PVA and sodium borate make?
A solution of polyvinyl alcohol (PVA) can be made into a slime by adding borax solution, which creates crosslinks between polymer chains. In this activity, some interesting properties of the slime are investigated.
Why does adding acid to PVA borax slime breaks the cross linking?
Throw a small piece onto a hard surface; it will bounce slightly. Adding acid to the slime breaks the crosslinking producing a liquid with lower viscosity. Adding alkali reverses the process and the slime should be regenerated.
How does the amount of borax affect slime?
The independent variable of the slime is the amount of borax because when you add more and more activator (borax) it is changing how much the slime stretches. The dependent variable is how long the slime can stretch because it is was happens in response to the amount of borax.
What is the purpose of the borax in the slime?
Borax in water forms an ion called the borate ion. When the borax solution is added to the glue solution, the borate ions help link the long polymer molecules to each other so they cannot move and flow as easily.
Why is slime a chemical change?
Slime activators (borax, saline solution, or liquid starch) change the position of the molecules in the glue in a process called cross-linking! A chemical reaction occurs between the glue and the borate ions, and slime is the new substance formed.
Does borax make slime stretchy?
Borax can be found in the laundry section of supermarkets. We can’t stress enough how important it is to not add too much borax solution – too much of the stuff will make your slime rubbery and break when you pull it, instead of being nice and stretchy.
Does borax make slime less sticky?
But the contact lens solution in the fluffy slime recipe that we make is the activator (like the borax) that also makes it less sticky.
What is the structure of PVA polymer slime?
Slime is sometimes described as a reversible cross-linking gel. The cross-linking between the polymer chains of polyvinyl alcohol occurs by adding borax, Na 2 B 4 O 7 .10H 2 O (sodium tetraborate). PVA glue contains, amongst other things, the polymer polyvinyl alcohol (also called polyethenol). Polyvinyl alcohol has the structure:
How to make slime with borax and alcohol?
Stir well. Measure out 10 cm 3 of borax solution into the beaker and add this to the polyvinyl alcohol solution, stirring vigorously until gelling is complete. This gel is sometimes known as ‘slime’. Wearing disposable gloves, remove the slime from the cup and knead it thoroughly to mix the contents completely.
How big of a beaker do you need for PVA slime?
It can be done by students in groups of two or three. Wear eye protection, and protective gloves if handling the slime. Polyvinyl alcohol, (- [CH 2 CH (OH)]n-) – PVA can be high MW (about 120 000) or low MW (about 15 000). If high MW PVA is used, prepare a 4% solution by placing 960 cm 3 of water into a tall 1 dm 3 beaker.
What is the structure of polyvinyl alcohol in PVA glue?
The structure of polymer polyvinyl alcohol (also called polyethenol), which is contained in PVA glue. Borax forms the borate ion when in solution. This ion has the structure: