The two main types of plastics are called thermosetting plastics and thermoplastics. Thermosetting plastics, once heated and cooled, cannot be reheated and remolded. Thermoplastics can be reheated and reshaped.
Examples of thermosetting plastics are silicones, urea aldehyde and Bakelite. The most common type of plastic is polyethene, which is a thermoplastic. Other types of thermoplastics include nylon, PVC and PVA.
The difference between the two types of plastics can be remembered by memorizing the term thermoSETting: Once set, thermosetting plastics cannot be reformed for another use. Plastics are synthetic materials that are human-made with polymers that are not found in nature.