Rubber materials play an important role in the marine and shipping industries. From dock fenders that absorb the impact of berthing vessels to marine hoses that transfer fuel and cargo, and vibration isolation pads that protect heavy machinery, rubber components are essential to the safe and efficient operation of ports and ships. These systems are required to operate in some of the harshest environments – exposure to saltwater, ultraviolet radiation, ozone attack, and continuous mechanical stress.
One defining aspect of marine rubber infrastructure is that they have long service life. Dock fenders, for example, are designed to be operated over a long period of time, 8-20 years is common, depending on operating conditions and maintenance. During this whole period, these rubber parts usually are installed directly on docks or off-shore structures and in constant contact with sea water and marine environments.
In order to preserve the durability of rubber in such demanding conditions, rubber formulations are usually based on stabilization systems such as antioxidants and antiozonants, including compounds such as 6PPD, IPPD and TDQ (TMQ). These additives are responsible for protecting the rubber from degradation caused by oxygen, heat, and ozone which leads to cracking and premature deterioration of the material.
However, concerns have been expressed about the ecological impact of some of these chemicals based on recent environmental research. Studies have demonstrated that when 6PPD combines with ozone, a transformation product called 6PPD-quinone is formed that has been proven to be highly toxic to some types of aquatic organisms. Scientific investigations have linked this compound to urban runoff mortality syndrome, a phenomenon that is responsible for sudden deaths of coho salmon in several waterways. Laboratory studies have shown that exposure to even very low concentrations of this transformation product can kill fish within hours.
While much of the research was initially focused on tire wear particles getting into waterways by way of stormwater runoff, the basic chemistry applies to many rubber products that contain similar stabilizing additives. This brings a very important question to marine infrastructure: what happens when rubber materials with these additives are left directly exposed to seawater for decades?
Marine rubber systems such as fenders and hoses are not a temporary material – they work continuously in sensitive aquatic ecosystems. Over any long service cycles, even small amounts of additive migration could result in cumulative exposure to the environment. As global shipping and port operations become more focused on creating a sustainable and environmentally responsible shipping environment, the materials used in marine infrastructure are attracting more attention.
This challenge has prompted forex researchers and material innovators to investigate bio-based solutions to traditional stabilization systems. Among the emerging technologies are lignin-derived antioxidant technologies, which hope to replace traditional additives for rubber compounds made from aromatic amines.
At Lignochem Composites Pvt. Ltd. , the research focus is on making such sustainable alternatives from lignin and its derivatives. Two examples of these materials are ECOLIN-RX and ECOLIN-RZ80 which are designed as bio-based stabilization systems for rubber applications.
The move towards lignin-based additives is an important step in ensuring that rubber technology is in line with wider environmental objectives. Lignin, a natural polymer that is plentiful in plant biomass, presents interesting antioxidant properties and will be a renewable alternative for petrochemical stabilizers that have been traditionally used in rubber formulations.
As the maritime industry continues to push towards greener ports, increased environmental standards and greater ESG commitments, material innovation will play an important role. Sustainable rubber chemistry can help to ensure that the very materials that are used to protect the ships and port infrastructure, also help to protect the oceans themselves.
The future of marine rubber may not only be stronger and longer lasting – but also greener and safer to marine ecosystems.