This week researchers from China’s Huazhong University of Science and Technology have developed a plastic material that degrades after only a week of sunlight and oxygen exposure.
The researchers were developing a polymer film that changes colour depending on pH levels, and working on an advanced type of chemical sensor. Due to the material’s unique molecular structure, and the chains of monomers whining, it offered the film a deep red colour and disappeared as soon as the bonds broke.
“In conjugated polymers such as this, which have a long backbone chain of alternating double and single bonds, the material’s color comes from its molecular structure – long chains of monomers – rather than a dye. Loss of that color means the chains have broken down into their monomer units,” explain researchers.
The team noticed that following several days of exposure to sunlight, the red colour of the film faded as the material broke apart. It is not uncommon for such bonds to be made breakable in research efforts to enable better recycling, however along the way the team inadvertently ended up developing a way to degrade plastic without affecting the environment.
Within a week of exposure to oxygen and sunlight, the material decomposed entirely, leaving no plastic residues that could harm the environment. While decomposing, the film released succinic acid, a naturally occurring by-product. Even so, the researchers believe that it could be reused in pharmaceutical or food industries.
But because it remains stable only in the dark and without oxygen, the molecular structure of this plastic won’t be suitable for shopping bags or storing food. It could be useful in some electronics or smartphones where the material would be sealed away from air and light in the device.
The team of researchers is working to find ways to make this plastic practical, along with other kinds of degradable plastics that can come into play. Still, they believe that commercial availability of this is 5-10 years away.
