Jiangnan University researchers found that squid ink melanin significantly improved the mechanical properties of polyurethane

If you want to have a more durable long lasting plastic foam or textile , the answer could lie in the animal’s skin, hair or eyes. Now researchers are using melanin, which occurs naturally in humans and other plants and animals, to make plastics stronger.

As we all know, polyurethane, as a kind of polymer synthetic material with excellent performance, is widely used in adhesives, construction, automobile and other industries. However, due to the thermodynamic incompatibility of its soft and hard segments, it has some performance defects. Usually, the chemical structure of polyurethane can be changed by stepwise polymerization of polyol and isocyanate, or the polyurethane can be modified by adding inorganic or organic fillers in the system to expand its application. Due to its special structure of soft and hard segments, it is difficult to realize the reinforcement and toughening of polyurethane at the same time.

Natural melanin (melanin) nanoparticles are macromolecules whose structural units contain a large number of phenolic hydroxyl groups, amino groups and carboxyl groups, and are widely found in animals and plants. At the same time, the groups in the nanoparticles have strong activity and can react with the isocyanate in the polyurethane prepolymer. Based on this, Wang Yang, a doctoral student in the research group of Professor Chen Mingqing and Dong Weifu from the School of Chemical Engineering, Jiangnan University, tried to extract melanin from squid ink sacs , and added it to ordinary polyurethane, when adding a small amount of melanin (2 wt%), the tensile strength and elongation at break of the material were increased from the original 5.6MPa, 770% to 51.5MPa and 1880%, while the material Toughness increased by 10 times. The mechanical properties of the polymer have been significantly improved. Compared with the current literature reports, its reinforcement effect is at a higher level, which is better than other nanocomposite materials, such as carbon nanotubes, graphene, cellulose and other reinforcement materials.

The relevant results were published in the international journal Biomacromolecules (2016, 17 (11): 3782–3789) under the title of “Superior Performance of Polyurethane Based on Natural Melanin Nanoparticles”. A few days ago, this achievement was reported as a research highlight by the American Chemical Society (ACS) newsweekly PressPac.