Which material is NOT a thermoset?

Which material is NOT a thermoset?

• A. Nylon
• B. Epoxy resin
• C. Silicone
• D. Bakelite

Answer: (A)

When a polymer cures into a rigid, three-dimensional network, it becomes a thermoset: it hardens irreversibly and doesn’t melt under heat. Thermoplastics, by contrast, are not crosslinked; they soften, melt, and can be reshaped when heated. Epoxy resin, Bakelite, and many silicone formulations cure to permanent networks, so they are thermosets. Nylon, on the other hand, is a thermoplastic; it can be heated, melted, and reformed without staying permanently set. This is why Nylon is not a thermoset.

When a polymer cures into a rigid, three-dimensional network, it becomes a thermoset: it hardens irreversibly and doesn’t melt under heat. Thermoplastics, by contrast, are not crosslinked; they soften, melt, and can be reshaped when heated.

Epoxy resin, Bakelite, and many silicone formulations cure to permanent networks, so they are thermosets. Nylon, on the other hand, is a thermoplastic; it can be heated, melted, and reformed without staying permanently set. This is why Nylon is not a thermoset.