The relationship between Kevlar and carbon fiber
Kevlar is a high-performance aramid fiber invented in 1965, belonging to organic synthetic fibers, while carbon fiber is an inorganic high-performance fiber. Both are core reinforcing materials of modern composite materials, but there are significant differences in structure, performance, and application.
What material is Kevlar?
core performance
Characteristic | Numerical/Performance | Comparison (vs. Carbon Fiber) |
Tensile Strength | Approximately 3620 MPa | Below carbon fiber (5000+MPa) |
Density | 1.44 g/cm³ | Lighter than carbon fiber (1.75-2.0 g/cm ³) |
Impact Resistance | Extremely strong (high energy absorption capacity) | Far superior to carbon fiber (carbon fiber has higher brittleness) |
High Temperature Resistance | Long term temperature resistance of about 200 ° C | Below carbon fiber (can withstand temperatures above 500 ° C) |
Resistant to cutting/puncture | Top tier (for bulletproof vests) | Carbon fiber is easily damaged by sharp objects |
Typical applications
Bulletproof protection
Bullet proof vests, helmets, and armored vehicle liners (due to their ultra-high energy absorption capacity).
industrial safety
Cut resistant gloves, high-temperature and fire-resistant clothing.
EADS
Aircraft cabin doors, helicopter bulletproof armor.
Sports equipment
Rowing and mountaineering ropes (lightweight and impact resistant).
Characteristics of Carbon Fiber
Chemical composition and structure
Main components: Graphitized fibers with a carbon content of over 90%, carbonized from polyacrylonitrile (PAN) or asphalt based precursor fibers.
Molecular structure: The graphite lattice is arranged along the fiber axis, endowing it with ultra-high stiffness and strength.
Characteristic | Numerical/Performance | Comparison (vs. Kevlar) |
Tensile Strength | 5,000-7,000 MPa | Higher than Kevlar |
Modulus (stiffness) | 200-900 GPa | Far higher than Kevlar (70-120 GPa) |
Compressive Strength | High (but brittle) | Kevlar has weak compressive strength but good toughness |
High Temperature Resistance | Inert environment can withstand 500 ° C+ | Better than Kevlar |
Conductivity/Thermal Conductivity | Conducting electricity and heat | Kevlar insulation |
Typical applications
EADS
Aircraft wings, satellite structures (high rigidity and lightweight).
Automotive Industry
Supercar body, F1 racing chassis (reduced weight and increased efficiency).
Sports Equipment
Golf clubs, bicycle racks (high rigidity).
Industrial sector
Mechanical arm, wind turbine blades (fatigue resistant).
Kevlar vs. Carbon Fiber: Key Differences
Comparing dimensions | Kevlar | Carbon Fiber |
Material type | Organic aramid fiber | Inorganic carbon materials |
Core advantages | Impact resistant, cutting resistant, flexible | Ultra high strength, high stiffness, high temperature resistance |
weakness | Weakly resistant to pressure and easily degraded by ultraviolet radiation | Brittle and afraid of sharp impacts |
cost | Medium (slightly lower than carbon fiber) | Higher (especially high-end products) |
Composite application | Often mixed with carbon fiber for use | Often used alone or in combination with fiberglass |
Collaborative application of Kevlar and carbon fiber
The two are often used in combination to complement each other’s performance
Bulletproof armor
Outer layer: Carbon fiber (high rigidity to resist the initial velocity impact of bullets)
Inner layer: Kevlar (absorbs residual energy and prevents fragments from splashing)
High performance sports equipment
Rowing boat (carbon fiber provides rigidity, Kevlar enhances impact resistance)
EADS
Helicopter bulletproof floor (carbon fiber+Kevlar laminate)
How to choose?
Kevlar and carbon fiber represent the two peaks of composite materials, known for their energy absorption and rigid load-bearing capabilities, complementing each other in high-end manufacturing.
Do you need impact resistance and flexible protection?
Choose Kevlar (such as bulletproof vests, anti cutting equipment).
Pursuing ultimate rigidity and lightweight?
Choose carbon fiber (such as airplane structures, supercar bodies).
Do you need both strength and toughness?
Mixed use (such as armor, high-end sports equipment).