5. Solving the plastic problem
Plastics are intertwined with our lives — driving researchers to create plant-based versions and more efficient ways to recycle, Alison writes.
The big picture: From a science perspective, the biggest challenge is consumers and companies want materials that won't degrade quickly while being used, but will degrade quickly once disposed, says Andrew Dove of the University of Birmingham in the U.K.
- "The world wants it both ways," he says.
How it works: Plastics are recycled or burned as a source of energy. But by one estimate, 79% of plastic waste has ended up in landfills or the environment.
- Plastics can be mixed with pigments, other materials and other plastics, which complicate recycling and limit how the chemical components of plastic can be reused.
The push for "green plastics" made from sustainable materials has given us cups made from corn-based plastic (polylactic acid) and compostable chip bags that can degrade.
Replacing petroleum-based plastics is still important in the long term, says Dove. But as it accumulates in landfills, researchers are increasingly focusing on new ways to make and recycle today's materials.
- Lawrence Berkeley National Laboratory researchers recently reported an alternative process for creating a plastic commonly found in epoxies and polyurethane.
- They were then able to break it down to its chemical building blocks, even when the plastics were colored or with other materials, and turn them back into plastic.
Scientists are also experimenting with degrading plastics using:
- Chemical recycling: Different acids and bases can be used to break down plastics. Researchers hope to develop chemicals that can selectively degrade a single type of plastic in a stream of mixed plastic waste.
- Enzymes: They have the advantage of being specific to a type of plastic but the disadvantage of working slowly compared to chemical recycling.