Tensile properties: In the 45° direction, the tensile strength of aramid/fiberglass warp-knitted composites increases by approximately 12%, while the flexural strength increases by about 21%.

Low-velocity impact performance: The maximum impact load of aramid/fiberglass warp-knitted composites increases by around 45%.

Flexural properties: In the 45° direction, the flexural strength of aramid/fiberglass warp-knitted composites is improved by about 26%, and the flexural modulus is enhanced by approximately 21%.

They can incorporate non-crimp, parallel-stretched reinforcing yarns at various angles, providing excellent reinforcement effects.
There is minimal crimping between fiber bundles, which promotes tight bonding between fibers.
Combined with liquid forming processes (such as RTM, RFI), they facilitate the production of composites and reduce manufacturing costs.
Stitching between layers enhances the damage tolerance and out-of-plane toughness of the composites.
Yarns bind the reinforcing fiber bundles, improving the interlayer performance of the warp-knitted fabric, resulting in excellent drapability and preformability.

Aramid fibers need surface modification primarily because their surface is relatively smooth and contains few polar groups, resulting in poor interfacial adhesion with the matrix materials (like rubber or plastic). This poor adhesion limits the effectiveness of aramid fibers in reinforcing composites. Surface modification increases the roughness and number of polar groups on the aramid fiber surface, thereby improving the interfacial adhesion with the matrix material and enhancing the overall performance of the composite material.

Kevlar fiber and aramid fiber are closely related but not exactly the same. Kevlar is a specific brand of aramid fiber developed by DuPont, known for its exceptional strength and heat resistance, commonly used in applications such as bulletproof vests and racing gear. Aramid fiber is a general category of synthetic fibers that also exhibit high heat resistance and tensile strength. While all Kevlar is aramid, not all aramid fibers are Kevlar, meaning Kevlar is a specific type within the broader category of aramid fibers.

Processing aramid fiber reinforcements presents certain challenges, including their inherent moisture sensitivity, which can affect bonding with resin matrices. Additionally, aramid fibers can be difficult to cut and shape due to their high strength, requiring specialized tools. Achieving consistent quality and performance in the final product also demands careful control of processing conditions, such as temperature and pressure during curing. Manufacturers often need to implement specific techniques, such as pre-treatments or surface modifications, to enhance adhesion and optimize performance in composite applications.

The orientation of aramid fibers plays a crucial role in determining the mechanical performance of reinforced composites. When fibers are aligned in the direction of the applied load, the composite exhibits significantly enhanced tensile strength and stiffness in that direction. Conversely, random or cross-oriented fiber arrangements can improve impact resistance and multi-directional strength but may reduce overall tensile performance. Engineers often optimize fiber orientation during the design phase to achieve the desired balance of strength, flexibility, and energy absorption specific to the intended application.

Para-aramid material, such as Kevlar, is known for its superior strength and stiffness compared to meta-aramid fibers, which are more flexible and heat-resistant but not as strong. This makes para-aramid ideal for high-performance applications where both strength and durability are critical.