Firm Develops Antifouling Paint Copper Replacement

THURSDAY, MARCH 17, 2022


Danish biotech company Cysbio recently announced that it has developed new sustainable replacement for copper in antifouling paints. According to reports, the company has developed and patented a fermentation technology to produce eelgrass acid as a copper replacement.

“Current antifouling paint is primarily based on older technology in the form of traditional biocides containing heavy metals, primarily copper, and it’s proven difficult to produce a more sustainable substitute,” said Henrik Meyer, CEO of Cysbio.

To find an environmentally friendly alternative, the company looked to biobased materials. Eelgrass, which grows on very low shores and in depths of 10 meters (32.8 feet) deep, can reportedly be used to prevent microbes and other larger organisms from attaching themselves to surfaces.

“Eelgrass only produces a tiny amount of eelgrass acid, so extraction directly from the eelgrass plant material is not affordable and production by chemical synthesis is also too expensive to allow commercial use,” Meyer explained.

“However, by brewing the acid, much like brewing beer, using our genetically engineered microorganisms to make eelgrass acid, we can make production much cheaper and based on renewable carbon sources, thereby making the whole process and the antifouling products fully sustainable.”

Without an antifouling coating, invasive organisms can attach a ship's hull and cause increased frictional resistance, fuel usage, shipping costs and decreased speeds. Additionally, these organisms can be spread to other ecosystems while the ship emits more carbon dioxide.

According to Cysbio, Sweden has fully banned ships with copper paint in the Bay of Bothnia and freshwater lakes, while the Netherlands and California has introduced restrictions that prohibit the sale of ship paint with high concentrations of copper for yachts and recreational vessels.

Meyer add that it’s “crucial” for companies to drive the development of sustainable alternatives.

“The current method with chemical and copper-containing paint is expensive and unsustainable, so it makes both economic and environmental sense to replace these less wanted components with more environmentally friendly solutions,” Meyer said.

Environmentally Friendly Antifoulants Research

In December, a study conducted by Egypt’s National Institute of Oceanography and Fisheries utilized algae to create environmentally friendly, antifouling marine paints.

For the study, researchers utilized extracts from four different Egyptian marine macroalgae: Ulva fasciata, Cymodocea nodosa, Padina pavonia and Colpomenia sinusa.

The water soluble polysaccharides (WSP), proteins and lipids were combined with paint into sixteen compositions, aiming to act as a biocide to create environmentally safe, antifouling marine paints. Each type of these algal extracts was mixed solely by 2% (w/w) for WSP and protein and 1% (w/w) for lipid with the prepared paint formulation.

These paints were applied to unprimed steel panels, hung on a steel frame alongside a control and submerged in the Eastern Harbour of Alexandria, Egypt. Researchers collected sea water samples to analyze during assessment, as well as visually inspected and photographed the panels.

After 171 days of immersion, results showed:

  • U. fasciata panels in both cases showed 25% and 30% of fouling organisms;
  • Protein extract of P. pavonia and C. sinusa panels coated showed 35% of fouling organisms; and
  • Protein extract of U. fasciata and lipid extracts of C. nodosa, P. pavonia and C. sinusa coated panels showed 40% and 45% of fouling organisms.

The best results were with panels coated with the formulations containing WSP. Researchers also report that the measured hydrographical parameters were within the normal range indicating that the paint compositions are environmentally safe.

In January, researchers at the University of Toronto reported they are looking at the adhesion of mussels on surfaces to potentially create new antifouling coatings for infrastructure and medical adhesives. 

The research team has reportedly been studying zebra and quagga mussels for years at the university’s material science and engineering research lab. These species are native to lakes and rivers in southern Russia and Ukraine, and likely made their way to the Great Lakes in North America in the 80s on ships from Europe.

Since these mussel species can be invasive and cause problems, like displacing native mussel species and fouling boats, water intake pipes and other infrastructure, the team decided to look at new techniques for measuring adhesion of zebra and quagga mussels to various surfaces to develop effective antifouling surfaces.

Using electron microscopy, researchers scanned the glue left behind on the surfaces after the threads were detached.

The team utilized a pair of fine-tipped, self-closing tweezers, a digital camera and a force gauge to measure how much force was required to break the protein-based glue secreted by the mussels. The mussels were collected from the wild and placed on glass, PVC and PDMS substrates to reattach.

Quagga mussels reportedly showed a significantly lower attachment rate on PDMS compared to glass and PVC, while the zebra mussels showed a consistent attachment rate across all three substrates.

Research found that overall the mussels adhered more strongly to glass than they did to plastics. According to the University of Toronto, researchers expected this since glass is inorganic and hydrophilic, similar to the rocks that the mussels use as substrates in nature, while PDMS repels water and is often coated on boat hulls to prevent biofouling.

The adhesive residue is known as a footprint, so the newly identified failure was named a “footprint failure” in the study. The occurrence of this failure indicates an incomplete detachment, demonstrating a strong adhesion from the mussels.

Their research is ongoing, testing on new types of surfaces to prevent fouling of critical infrastructure, as well as investigating the differences in adhesion between freshwater and marine mussels.

   

Tagged categories: Antifoulants; Asia Pacific; Bio-based materials; Coating Materials; Coatings technology; Coatings Technology; Copper; EMEA (Europe, Middle East and Africa); Environmental Controls; Environmentally friendly; Green coatings; Latin America; Marine Coatings; North America; Paint; Research and development; Ships and vessels; Sustainability; Z-Continents

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