A new plastic that is biodegradable and can be recycled

The new polymer synthesis process. The single molecules (monomers) are cooled to polymerize; to cycle back, heat is applied. Credit: Jing Tang/Chen lab

It is now a bit more than a hundred year since plastic was invented (back in 1907). At that time nobody imagined that plastic would turn out to be a major issue in terms of polluting the ambient. 

Every year over 5,000 billion plastic bags are produced and each one of them is likely to have a lifetime of about a thousand years! Oceans have became plastic landfill killing fish and swimming mammals, like dolphins.

An interesting book, The world without us, by the American journalist Alan Weisman, points out that the last signs that humans were on the Earth after their demise, would be plastic, over lasting all our artefacts.

Scientists have been at work in the last thirty years to find a biodegradable and recyclable polymer (the scientific name for plastic). Some have even claimed that it is an impossibile goal.  Notice that biodegradable requires that the polymer decomposes over time in the environment (the shorter the time, the better) whilst recyclable requires that the compounds resulting from the degradation can be reused to create polymer chains.

We have been able to create biodegradable polymers (like the P4HB - poly4-hydroxybutyrate) but these are more costly to produce (interestingly the P4HB has been created by mimicking a bacteria capability to produce polymers) and they are not recyclable.

Now a team of chemists at the University of Colorado have announced completely recyclable polymers. They have created a polymer that at ambient temperature with the appropriate catalyst can be decomposed into monomers that in turns can be used (by heating them) to create the polymer.

Most importantly, the process involved in both de-polymerization and in polymerisation is within the cost range of other industrial polymerisation processes.

The dream of a plastic that can dissolve in the environment and that can be easily recycled seems to become a reality.

Author - Roberto Saracco

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