There are metal-plastic polymers

plastic

A plastic bag, for example, melts on a hot stove and becomes deformed. This group of plastics is called thermoplastics. Plastics that can withstand heat and retain their shape are called thermosets. Elasticity is also an important property of plastics: the elastomers retain their shape and - despite bending, squeezing and pressing - always return to their original shape.

Plastics of the future made from renewable raw materials

The plastics industry has to rethink. Oil is expensive - and there is not an infinite amount of it. "The future belongs to bioplastics," says researcher Ramón Català. These can be made from renewable raw materials such as soy, corn, sugar cane and even animal remains.

At the Institute for Food Technology and Agro-Chemistry in Valencia, Català and his colleagues are working on a plastic made from the shells of crustaceans such as shrimp, made from chitosan. "This raw material is available in abundance as a waste product from the food industry. It is just waiting to be put to good use," explains Català.

The bags of some supermarket chains already consist partly of corn or cellulose. In order to make the bags tear-resistant, conventional plastic is usually added.

Plastic films that kill germs

Researchers around the world are looking for ways to add new properties to plastics. In the future, plastics should also actively interact with the environment - and keep food fresher longer, for example. The new plastic packaging traps the gases that cause fruit and vegetables to ripen. "Many of these plastics are still in their infancy," says Català. So far, no product has been able to survive on the market.

At the University of Bonn, a research group is working on packaging that has an antimicrobial effect and thus extends the shelf life of meat products. The film in which the meat is packed is hydrophobic and has a strong positive charge. It attracts bacteria and breaks their cell walls when they come into contact with them.

"Initial tests have shown that no microorganisms survive on the new material," says project manager Judith Kreyenschmidt. If the further tests do not reveal any undesirable side effects, the antimicrobial plastic could be on the market in five to seven years, the researcher estimates.

Plastics harm the environment

"Compared to steel, wood or metal, plastic is a relatively inexpensive material," says Franziska Krüger from the Federal Environment Agency. In addition, the plastics make it possible to build lighter vehicles, to insulate buildings better and thus to reduce energy consumption. That protects the environment.

However, plastic does not have a good reputation. Many of the plastics are harmful to the environment, including polyvinyl chloride. It contains up to 57 percent chlorine. If it burns, it produces highly toxic chlorine compounds and acids. Disposing of the pollutants is very time-consuming and expensive.

If the plastic is released into the environment, it will take many years to completely decompose. According to estimates, more than 100 million tons of plastic lie dormant in the world's oceans alone. It breaks down into smaller and smaller fragments. Marine animals such as fish, crabs and turtles snap up the particles. Chemicals that are harmful to health dissolve. It can also harm people.