| Both types of plastic, thermoplastics and thermosetting plastics, can be formed through casting and expansion processes. Casting forms plastic objects in a mold. After the plastic is poured in the mold, additives mixed into the plastic cause the resin to harden. Expansion processes inject gases into the plastic melt, creating a foam plastic from the tiny bubbles trapped inside. Styrofoam contains a chemical that produces gas as it is heated. As the styrofoam cools and hardens, tiny bubbles left inside the material from the gas create a foam plastic. |
Hotmail
Messenger
My MSN
MSN Directory
