Published: 2025-07-30 13:52:56
Research and application of new seawater-resistant cable materials
With the rapid development of marine resource development, marine engineering construction, and maritime communications, the performance requirements for seawater-resistant cables are becoming increasingly stringent. Traditional cable materials have gradually revealed many limitations when facing complex marine environments, such as high-salinity seawater corrosion, seawater pressure, mechanical external forces, and biological adhesion. Therefore, research and application of new seawater-resistant cable materials have become industry focuses, aiming to enhance the reliability, durability, and safety of cables in marine environments.
Background of the R&D of new seawater-resistant cable materials
The marine environment is extremely complex, with seawater salinity typically around 3.5% and rich in corrosive ions such as chloride and sodium ions, posing severe challenges to the corrosion resistance of cable materials. Moreover, as marine development moves deeper into the sea, cables must endure greater seawater pressure. In shallow areas, mechanical forces generated by waves and tides, as well as ship towing and friction against seabed rocks, can all cause cable damage. At the same time, the attached growth of marine organisms not only increases cable weight but may also damage the cable structure, affecting its performance. Traditional cable materials such as ordinary rubber and polyvinyl chloride (PVC) cannot operate stably in such environments for long periods, making the development of new materials urgent.
Representative new materials and their properties
Thermoplastic Polyurethane (TPU)
TPU is a high-performance thermoplastic elastomer intermediate between rubber and plastic, widely used in seawater-resistant cables. Its molecular structure is stable and it has excellent resistance to hydrolysis. Polyether-type TPU ether-ester mixed chain segments, after 3000 hours of ASTM D543 testing, retain ≥85% elongation at break, and crystallize in hard segments to form physical crosslinking points, effectively suppressing water molecule diffusion and penetration. In terms of salt spray corrosion resistance, the strongly polar carbamate ester group (-NHCOO-) in TPU molecules forms dense hydrogen bonds, with chloride ion permeability only 1/10 that of PVC. Adding nano montmorillonite sheets further extends the diffusion path. In terms of mechanical properties, TPU has excellent wear resistance (DIN 53516 ≥15,000 rpm), able to withstand hull friction and guide wheel compression; It has high elastic recovery capability, can quickly recover after repeated bending, and suppresses crack initiation; It has good low-temperature toughness, can operate normally in -40°C environments, and is suitable for low-temperature working environments such as polar seas.
High-performance fiber-reinforced materials
High-performance fiber reinforcement materials such as carbon fiber reinforced polyethylene (CFRPE) and glass fiber reinforced plastic (GFRP) are also gradually being applied in seawater protection cables. Taking CFRPE as an example, carbon fiber has high strength and low density. When combined with polyethylene, it greatly increases the cable's tensile strength, which can be 2 to 3 times higher than ordinary submarine cable materials, effectively enhancing its load-bearing capacity under seawater tension and drag, ensuring cable structural integrity, and reducing the cable's own weight, making installation easier. GFRP also has a high strength-to-weight ratio, providing cables with excellent compressive and bending resistance, making them less likely to deform or break under complex marine external forces.
Nanocomposites
The development of nanotechnology brings new opportunities for innovation in seawater-resistant cable materials. By adding nanoscale fillers such as carbon nanotubes, graphene, and nano-montmorillonite to traditional cable material substrates, material properties can be significantly improved. For example, composite materials with carbon nanotubes have improved conductivity, mechanical properties, and thermal stability. Carbon nanotubes have excellent electrical properties, enhancing cable conductivity and reducing signal transmission losses; In terms of mechanical properties, they effectively improve the material's strength and toughness, resisting seawater pressure and mechanical forces. Graphene has an extremely large specific surface area and excellent barrier properties; when added to cable materials, it forms a dense barrier layer that blocks seawater erosion and improves corrosion resistance. Nano montmorillonite flake structures can form winding paths inside the material, delaying the diffusion of corrosive media and enhancing the material's corrosion resistance.
Application of new materials in various marine scenarios
Offshore wind farm
In offshore wind farms, cables are responsible for power transmission and signal communication between wind turbines and between turbines and onshore. TPU-sheathed cables, with their salt spray resistance, waterproof degradation, and softness, vibration resistance, make them the ideal choice for connecting offshore wind turbine control systems and enabling power transmission, extending cable service life to over 10 years. At the same time, cables made from high-performance fiber-reinforced materials can better withstand the impact of sea breezes and waves on the turbines as well as the cable's own weight, ensuring stable power transmission.
Port and terminal facilities
Automated equipment in ports and terminals, such as quay cranes, gantry cranes, stackers, etc., require frequent movement and towing of cables for power supply and control systems. TPU cables can be frequently bent and stretched, have strong compressive and friction resistance, and have smooth surfaces that are not prone to water and dust accumulation, making them especially suitable for drag chain systems and movable cable reels in port machinery. Additionally, to prevent salt spray corrosion, some cables use materials with corrosion-resistant coatings to ensure long-term stable operation of equipment in harsh port environments.
Underwater detection and operational equipment
Underwater robots (ROV/AUV), marine exploration equipment, and similar cables operate in deep-sea environments and require extremely high cable performance. TPU cables are dense, have extremely low waterproof permeability, and excellent compression resistance, effectively preventing seawater infiltration. They also have excellent wear and tear resistance to ensure stable equipment operation. Cables made from nanocomposite materials, with their outstanding electrical and mechanical properties, can achieve precise signal transmission and stable power supply in deep-sea high-voltage, low-temperature, and complex electromagnetic environments.
Marine aquaculture facilities
In marine aquaculture, cables are used for wiring sensors, electric gates, lighting systems, and other equipment in fish farming cages. New seawater-resistant cable materials such as TPU have excellent antimicrobial and hydrolysis-resistant properties and do not degrade in performance due to erosion by algae, fungi, or bacteria, ensuring long-term stable use of cables in saline, alkaline, and microbe-dense environments, thus guaranteeing the normal operation of marine aquaculture facilities.
Challenges and development trends in the application of new materials
Although new seawater-resistant cable materials show many advantages, they still face some challenges in application. On one hand, some new materials, such as high-performance fiber-reinforced materials and nanocomposites, have complex preparation processes and high costs, limiting their large-scale application. On the other hand, the long-term performance stability of new materials in complex marine environments still needs to be further verified through extensive practical applications and long-term monitoring data.
Looking ahead, new materials for seawater-resistant cables will develop in the following directions: first, continuously reducing costs by optimizing the preparation process and seeking more economical raw materials to improve the cost-performance ratio of new materials and promote their wider application; second, further enhancing the comprehensive performance of materials, such as developing intelligent materials that simultaneously possess higher strength, better corrosion resistance, superior electrical performance, and self-healing capabilities; third, focusing on the environmental friendliness of materials by developing recyclable and eco-friendly materials to reduce potential impacts on the marine ecological environment.
The research and application of new sea-resistant cable materials provide strong support for the development of marine-related industries. With continuous technological advancements, these materials will play a greater role in marine engineering, helping the development and utilization of marine resources reach new heights.