Which reinforcement fiber typically has the lowest density?

Which reinforcement fiber typically has the lowest density?

• A. Carbon fiber
• B. Glass fiber
• C. Aramid (Kevlar)
• D. Basalt

Answer: (C)

Density is mass per volume, so lighter fibers give you less weight for the same size. Among common reinforcement fibers, aramid fibers (like Kevlar) are the lightest. Their polymeric aromatic amide structure uses lighter elements and lacks heavy inorganic components, giving a density around 1.4 g/cm³. In contrast, carbon fibers sit around 1.7–1.95 g/cm³, while glass and basalt fibers are about 2.5–2.7 g/cm³. This low density makes aramid fibers particularly favorable for weight-sensitive applications, though they may trade some stiffness and high-temperature performance for the weight savings.

Density is mass per volume, so lighter fibers give you less weight for the same size. Among common reinforcement fibers, aramid fibers (like Kevlar) are the lightest. Their polymeric aromatic amide structure uses lighter elements and lacks heavy inorganic components, giving a density around 1.4 g/cm³. In contrast, carbon fibers sit around 1.7–1.95 g/cm³, while glass and basalt fibers are about 2.5–2.7 g/cm³. This low density makes aramid fibers particularly favorable for weight-sensitive applications, though they may trade some stiffness and high-temperature performance for the weight savings.