Editing Diaper Polymers (section)

===Full Explanation===
A diaper needs to be able to absorb liquid without leaking. This task is done by the use of ''Polymers'', identical molecules that connect to each other end to end. The polymers that we are all most familiar with are plastics, and the majority of plastics are hydrophobic. ''Hydrophobic'' materials are ones that, when water is poured or spilled on them, repel water and don't absorb any of it. This is because, on the molecular level, the bonds between the molecules are close enough and strong enough to prevent water from passing through them. The outer layer of a diaper is made of plastic because of this, so that the diaper won't leak onto an unsuspecting parent or caregiver.

The pad inside of a diaper is highly absorbent. Part of the absorption is because of the type of pad, but a large amount of the absorption is because of what is added to the pad. Diaper pads have crystallized ''Sodium Polyacrylate'', a ''Polyacrylic Acid'' salt, added into them. These crystals are tiny, and when dry they don't look like much. However, these crystals become quite amazing once they are wet. Polyacrylic acid becomes a polymer when wet, causing the crystals throughout the diaper to start linking together. Polyacrylic acid is also ''Hydrophilic'', a material that readily absorbs water and will expand several times its size to try to absorb more of it. In this case, the crystals will expand to absorb up to 300 times their mass in water!

{| class="wikitable" style="color:black; background-color:#ddd; text-align: center; margin: auto"
| Sodium Polyacrylate (Anhydrate)
| Polyacrylic Acid (Hydrated)
|-
| [C<sub>3</sub>H<sub>3</sub>NaO<sub>2</sub>]<sub>n</sub>
| [C<sub>3</sub>H<sub>3</sub>O<sub>2</sub><sup>-</sup> + Na<sup>+</sup>]<sub>n</sub> + N H<sub>2</sub>O
|}

When the sodium polyacrylate is in water, the sodium separates from the polyacrylic acid. Polyacrylic acid doesn't dissolve in water solutions, however, and it will start connecting with the other polyacrylic acid moelcules. Even though each of them have a net negative charge, they bond together because the negative charge is isolated to one of the oxygens, which allows the carbons to bond with each other by passing a hydrogen up to the oxygen. This makes polyacrylic acid an '' Anionic Polyelectrolyte'', a chemical that becomes a polymer when it loses one of the positive charges in solution. The water molecules become encased in the polymer, since it can only form while the sodium is dissolved in the water, and the polymer will actively absorb as much water as possible in order to better contain the sodium ion. This is why the polymer will absorb as much as 300 times its mass in water!

When we add the salt to the solution, we are flooding the solution with excess sodium. The extra sodium starts to bond with the polyacrylic acid, which breaks the polymer and causes it to fall apart. The crystals will still hold onto water, but the salt increases the molar mass of the solution, which causes the crystals to lose some of it. This results in the crystal gel falling apart and "melting" back into solution. This final solution is safe to pour down a drain because of the added salt as well; The leaking crystals have some of the salt trapped inside of them now, so their ability to absorb water is compromised.