Vacuum forming is used on which type of plastics?

• A. Thermoplastics
• B. Thermosets
• C. Elastomers
• D. Ceramics

Answer: (A)

Vacuum forming relies on heating a plastic sheet until it becomes soft and then pulling it over a mold with a vacuum so it shapes and hardens as it cools. That behavior—softening when heated and solidifying again upon cooling—is a hallmark of thermoplastics. Thermosets, once cured, don’t melt or soften, so they can’t be reshaped by this process. Elastomers are rubbery and often don’t provide the rigid, stable shapes vacuum forming typically aims for, and ceramics aren’t plastics and don’t melt to reform under heat. So the plastics used for vacuum forming are thermoplastics, such as polystyrene, acrylic, and polycarbonate.