Which plastic category is commonly used in reinforced composites?

• A. Thermoplastic
• B. Elastomer
• C. Thermoset
• D. Bioplastic

Answer: (C)

Reinforced composites rely on a matrix that binds fibers and transfers load to them. Thermoset resins fit this role best because, once cured, they form a rigid, crosslinked network that provides high stiffness, strength, and excellent thermal and environmental resistance. This strong, stable matrix bonds well with fibers such as carbon or glass, giving the composite its structural integrity and dimensional stability under load and heat. Elastomers are too soft for structural reinforcement, and while thermoplastics can be used in some composites, they don’t typically offer the same combination of stiffness and heat resistance as thermosets for high-performance structural parts. Bioplastics aren’t generally chosen for reinforced structural composites due to performance and processing constraints. So the commonly used category is thermoset.