Chemists in search of their Holy Grail: a plastic designed to die
Plastics were designed to last as long as possible, but they’re now blamed for billions of tons of waste choking the planet. So chemists are on a quest to make new materials: polymers or plastics with a built-in self-destruct mechanism, degradable on command.
Adam Feinberg had no sooner made a thin, bright yellow sheet of plastic that he had to shred it into little pieces. He chose an “I”-shaped mold for the logo of the University of Illinois at Urbana-Champaign, where he is a chemist. Then, he filled it with the plastic bits and stuck it in a hot oven.
“I opened up the mold and there was this beautiful yellow ‘I,’ ” he recalled. His new plastic passed the first test: It was moldable with heat, like regular plastic. But there was another important step left in rethinking the world of durable plastics.
Feinberg placed the “I” under a white light, and five minutes later, only half of it remained. The other half had fallen on the ground. Pieced back together, the “I” had a hole in the middle and in its place was yellow goo.
The plastic did not simply melt. Its building blocks, the synthetic polymers within, had reverted to their molecular units. “It was a phenomenal feeling,” he said of the successful experiment.
But synthetic polymers became so popular and adaptable that decades later, they are at the root of the global burden of billions of tons of plastic waste. The latest villains in environmental campaigns are disposable plastic products formed from synthetic polymers — straws, cigarette filters, coffee cup lids, etc.
During the past few decades, this mismatch between material and product lifespan has built up plastic waste in landfills and natural environments, some drifting in oceans until mounds and mounds have reached the ends of the world and bits have been ingested by marine life. Too little gets recycled; in fact, some estimates indicate that a mere 10 percent of all plastics are recycled every year.
Image courtesy of seattletimes.com