Seaweed transforming into a protective shield around a house, symbolizing fire safety.

Is Your Furniture a Fire Hazard? The Science of Flame-Retardant Coatings

Rhea Morgan in Science & Nature August 2025 • 4 min read.

"Discover how scientists are using seaweed and other sustainable materials to create safer, flame-retardant furniture and building materials, protecting your home and family."

In today's world, where safety and sustainability are increasingly important, the materials that make up our homes and offices are under greater scrutiny than ever. Waterborne epoxy, known for its versatility and strong adhesion, is widely used in everything from steel structures to household items. However, its flammability poses a significant risk, spurring researchers to seek safer alternatives to traditional flame retardants.

Traditional flame retardants often contain harmful chemicals, leading to health and environmental concerns. This has driven the search for eco-friendly options that don't compromise safety. One promising solution lies in the ocean: seaweed. Scientists have discovered that a substance derived from seaweed, called phosphated K-carrageenan (P-KC), can be used to create effective, non-toxic flame-retardant coatings.

This article delves into the groundbreaking research on P-KC and its application in waterborne epoxy coatings. We'll explore how this natural material enhances flame retardancy, offering a sustainable and safer approach to protecting our living spaces. Join us as we uncover the science behind this innovative solution and its potential to revolutionize the future of fire safety.

How Does Seaweed Become a Flame Retardant?

Seaweed transforming into a protective shield around a house, symbolizing fire safety.

The journey from seaweed to flame retardant is an intriguing one. Researchers begin with K-carrageenan (KC), a polysaccharide extracted from seaweed. This material is then chemically modified through a process called phosphorylation, resulting in phosphated K-carrageenan (P-KC). The phosphorylation process involves reacting KC with phosphorus oxychloride (POCl3), which introduces phosphate groups into the K-carrageenan structure. These phosphate groups are key to P-KC's flame-retardant properties.

To enhance the flame retardancy of waterborne epoxy, P-KC is combined with another compound called 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, commonly known as DOPO. DOPO is an organic phosphorus compound known for its flame-retardant capabilities. When P-KC and DOPO are added to waterborne epoxy, they work together to create a synergistic effect, boosting the material's resistance to fire.

Preparation of P-KC:
- K-carrageenan (KC) extracted from seaweed.
- KC reacted with phosphorus oxychloride (POCl3) to form phosphated K-carrageenan (P-KC).
Addition of DOPO:
- P-KC combined with DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide).
- DOPO enhances the flame-retardant properties of P-KC.
Application in Waterborne Epoxy:
- P-KC and DOPO mixed into waterborne epoxy coatings.
- The combination improves fire resistance through a synergistic effect.

The effectiveness of P-KC and DOPO in enhancing flame retardancy was evaluated through rigorous testing, including cone calorimeter tests. These tests measure how the material behaves when exposed to heat and fire, assessing key factors such as total heat release (THR) and total smoke production (TSP). The results showed that the combination of P-KC and DOPO significantly reduced both THR and TSP, indicating a substantial improvement in flame retardancy. In particular, a specific mass ratio of DOPO to P-KC (2:1) proved most effective, decreasing THR by 48.7% and TSP by 37.4%.

The Future of Fire Safety: Sustainable and Effective Solutions

The development of phosphated K-carrageenan as a flame retardant represents a significant step forward in creating safer and more sustainable materials. By harnessing the power of seaweed and combining it with other flame-retardant compounds like DOPO, scientists are paving the way for a future where our homes and buildings are protected by eco-friendly solutions. As research continues and new innovations emerge, we can look forward to a world where fire safety and environmental responsibility go hand in hand.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.3390/polym10111268, Alternate LINK

Title: Synthesis Of Phosphated K-Carrageenan And Its Application For Flame-Retardant Waterborne Epoxy

Subject: Polymers and Plastics

Journal: Polymers

Publisher: MDPI AG

Authors: Na Wang, Haiwei Teng, Long Li, Jing Zhang, Ping Kang

Published: 2018-11-15

Everything You Need To Know

How is phosphated K-carrageenan (P-KC) made from seaweed, and how does it work as a flame retardant?

Phosphated K-carrageenan (P-KC) is created from K-carrageenan (KC), a polysaccharide extracted from seaweed. KC is chemically modified through phosphorylation, reacting it with phosphorus oxychloride (POCl3). This process introduces phosphate groups, which give P-KC its flame-retardant properties. To enhance these properties further, P-KC is combined with DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide), creating a synergistic effect that significantly boosts fire resistance when added to waterborne epoxy coatings.

What are cone calorimeter tests, and how do they demonstrate the effectiveness of phosphated K-carrageenan (P-KC) and DOPO in enhancing flame retardancy?

Cone calorimeter tests are used to evaluate the effectiveness of flame retardants like phosphated K-carrageenan (P-KC) and DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide). These tests measure how materials behave when exposed to heat and fire, specifically assessing total heat release (THR) and total smoke production (TSP). A lower THR and TSP indicate better flame retardancy. For example, a 2:1 mass ratio of DOPO to P-KC decreased THR by 48.7% and TSP by 37.4%.

Why is waterborne epoxy used so widely, and what makes finding a flame-retardant alternative like phosphated K-carrageenan (P-KC) so important?

Waterborne epoxy is used in various applications, including steel structures and household items, because of its strong adhesion and versatility. However, it's also flammable, posing a safety risk. Researchers are exploring alternatives like phosphated K-carrageenan (P-KC) derived from seaweed. Traditional flame retardants often contain harmful chemicals, so using P-KC offers a safer, more sustainable option.

How does using phosphated K-carrageenan (P-KC) as a flame retardant reflect broader trends in sustainability and safety?

The use of phosphated K-carrageenan (P-KC) as a flame retardant aligns with the increasing importance of sustainability and safety in materials science. Traditional flame retardants often contain harmful chemicals that pose health and environmental risks. By using a non-toxic, seaweed-derived substance like P-KC and combining it with DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide), we can create safer living spaces without compromising environmental responsibility.

What are the next steps in research and development for flame retardants like phosphated K-carrageenan (P-KC), and what other innovations might we see in the future of fire safety?

The combination of phosphated K-carrageenan (P-KC) and DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) in waterborne epoxy coatings offers a promising avenue for enhancing fire safety. However, further research is needed to optimize the performance of P-KC with different types of polymers and assess its long-term durability and environmental impact. Additionally, exploring other sustainable materials and flame-retardant compounds could lead to even more effective and eco-friendly solutions.