How did nylon and Kevlar change the design of modern body armour?

The development of nylon and Kevlar fundamentally transformed modern armour by shifting from heavy, rigid materials to lightweight, energy-dissipating textiles.

• Nylon: During the mid-20th century, nylon was used in vests like the M-1952 to provide protection against shell fragments. Researchers later discovered that multiple layers of tightly woven nylon could deform a bullet and dissipate its kinetic energy, allowing the fabric to "catch" the projectile rather than simply attempting to be impervious to it.12
• Kevlar: Introduced in 1971, this high-strength aramid fibre is five times stronger than steel by weight. Kevlar allowed engineers to create significantly more effective, lightweight body armour. These advanced fibres absorb the impact of bullets or fragments, dispersing their energy across a large area as the projectile moves through successive layers.345

Today, soft vests made of these fibres provide essential protection against handguns and fragments, while the integration of advanced ceramics into these designs enables protection against high-velocity rifle rounds.5