Materials

Extracted pigment makes for stronger plastic

Extracted pigment makes for st...
The scientists obtained melanin from cuttlefish, which manipulate the pigment to alter their appearance
The scientists obtained melanin from cuttlefish, which manipulate the pigment to alter their appearance
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The scientists obtained melanin from cuttlefish, which manipulate the pigment to alter their appearance
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The scientists obtained melanin from cuttlefish, which manipulate the pigment to alter their appearance

If you want longer-lasting plastic foams or textiles, the answer may lie in your skin, hair and eyes. All of those body parts get their color from a naturally-occurring pigment known as melanin, which is also found in other animals. Now, scientists from China's Jiangnan University have determined that even a small amount of added melanin makes polyurethane much stronger.

In lab tests, a team led by Mingqing Chen and Weifu Dong started by extracting melanin from ink sacs of cuttlefish and blending it into ordinary liquid polyurethane.

Even when the resulting cured foam contained as little as two percent melanin, it still exhibited about a 10-fold increase in both toughness (impact-resistance) and tensile strength (stretchability). Whereas unaltered polyurethane could stretch by 770 percent before breaking, the foam with added melanin was able to get to 1,880 percent.

According to the scientists, this increase was at least partly due to the melanin nanoparticles' tendency to link with the polymer chains that make up the polyurethane.

A paper on the research was recently published in the journal Biomacromolecules.

Source: American Chemical Society

5 comments
5 comments
Bob Stuart
Tensile strength refers to the force at fracture, not the elongation. Please re-learn English from an engineering glossary. Strength, stiffness, and toughness are not even slightly interchangeable terms in a technical article.
Aross
Oh, great, more and longer lasting plastics to pollute the planet. Its time we stopped making this garbage and go back to natural, bio-degradable products.
StWils
What the implications for producing a totally organic foam resin, both parts A&B, from renewable sources that can be domestically grown? Also does a stronger polyurethane resin portend an improved aerogel foam that has the tremendous insulation value of current aerogels but with a durability that permits actual real world usage? Given the national disaster that occurred Tuesday it would be great if ongoing research could yield vastly improved products that DO NOT require petrochemicals.
yona
Could it be that the melanin do not exists as a nanoparticle in the foam , but rather is dissolved in the polyurethane and reacts with polyurethane end groups? In fact, based on the molecular structure of melanin, it may act a crosslinker in the polyurethane network.
ljaques
Since about 90% of the plastic items I throw away are due to the fragility of the plastic, this is a good thing. It will mean that far fewer pieces of plastic will be made so far less gets into the garbage stream. BUT, is it recyclable after the addition of the melanin? I would hope so. Our new President might be able to bring some factories home and they can use this new formulation with American workers.