Unlike glass fiber, aramid fiber is a type of high-performance synthetic fiber. When used to reinforce RTP pipes, it imparts exceptional performance characteristics, as outlined below:

Aramid fibers exhibit a tensile strength of approximately 2,800–3,200 MPa—1.5 to 3 times that of glass fibers (1,000–2,000 MPa). Critically, aramid has a much lower density (only 1.44 g/cm³) compared to glass fiber (~2.5 g/cm³), resulting in a superior strength-to-weight ratio. This advantage enables aramid-reinforced RTP pipes to withstand higher working pressures (typically 3–32 MPa, with some specialized variants reaching up to 40 MPa).

Aramid fibers offer robust resistance to cyclic stress. This property makes aramid-reinforced RTP pipes far less susceptible to cracking under long-term alternating pressure conditions (e.g., pulse pressure in oil and gas production). As a result, such pipes boast an extended design life of 20–50 years.

Aramid fibers feature a high elastic modulus, delivering greater rigidity than glass fiber. They also provide enhanced creep resistance—meaning they resist deformation when subjected to prolonged pressure. These traits make aramid-reinforced RTP pipes ideal for stable, long-term high-pressure fluid conveyance.

Aramid fibers demonstrate excellent chemical stability against a wide range of substances, including acids, alkalis (with the exception of strong oxidants like concentrated nitric acid), hydrocarbons, and brine. When paired with a corrosion-resistant thermoplastic matrix (e.g., PVDF), aramid-reinforced RTP pipes can safely transport corrosive fluids such as H₂S and CO₂—eliminating the need for additional anti-corrosion coatings.

However, aramid fibers also have a shortcoming in compression resistance.

A notable limitation of aramid fibers is their “strong in tension but weak in compression” characteristic. This translates to aramid-reinforced RTP pipes being prone to deformation when subjected to external extrusion forces—for instance, soil pressure during underground burial or mechanical impacts during installation. To mitigate this risk, additional protective measures are required, such as using thickened outer jackets or laying protective cushions around the pipe in burial scenarios.

In conclusion, the high cost of aramid fibers restricts their application in conventional medium-low pressure scenarios. For such use cases, glass fiber-reinforced RTP pipes are typically the preferred, cost-effective alternative.

Three-Layer Design:

• Inner Liner: Typically made of thermoplastics like HDPE, PE-RT, or PVDF, providing chemical resistance and fluid containment.
• Reinforcement Layer: Composed of aramid fibers (e.g., Kevlar®), which offer exceptional tensile strength (modulus of elasticity: 70–100 GPa) and resistance to fatigue compared to polyester or glass fiber.
• Outer Jacket: A protective thermoplastic layer (e.g., HDPE with UV stabilizers) shields the reinforcement from external abrasion and environmental degradation.