Question

Three-dimensional molecules with cross-links are formed in the case of a:

• A. thermosetting plastic
• B. thermoplastic
• C. both (a) and (b)
• D. none of the above

Answer 1

Answer: (A)

Thermosetting plastic consists of chain of the molecules which are cross-linked, with each other when heated. When thermosetting plastics cross-link, the molecules create a permanant, network which is a $3-D$ structure and can be considered one giant molecule. Once cured, thermosetting plastic cn not be remelted, in the same way that cured concrete cannot be reset.