Promising polymers also pose problems

As a physical chemist familiar with polymers, I enjoyed the commentary “The promise of polymers” by Timothy Lodge (Physics Today, December 2017, page 10 ). Those molecules, with their remarkable versatility and properties, have contributed much to human society to date and promise even more wonders for the future. As an environmentally concerned citizen, however, I was disappointed with the short shrift given to the environmental problems caused by plastics―just two sentences in the three-page article.

Some 8 million metric tons of plastic waste currently enter the world’s oceans from land-based sources each year. The accumulation of that nonbiodegradable substance threatens, at a minimum, marine populations, which are already under stress from overfishing, ocean warming and acidification, and chemical pollutants.

Despite decades of discussion about developing biodegradable plastics, particularly for the packaging of foodstuffs and consumer items, neither industry nor academia has come up with an affordable plastic that is sufficiently stable for its purpose yet will biodegrade in a reasonable amount of time after its use. Many plastics, such as polyethylene, are nearly 100% pure hydrocarbons, yet an environmentally safe technique has not been developed to use them as a fuel source on a large scale. In addition, no serious attempt has yet been made to remove plastic from the ocean gyres, where it has been accumulating in concentrations sufficient to make a cleanup feasible. Given today’s available talent and technology, those three shortcomings are remarkable.

The rosy future of plastics, as presaged in the movie The Graduate and aptly described by Lodge in his commentary, could be a very mixed blessing if we end up soiling our nest. With more than two billion additional humans predicted to arrive on our planet before the population stabilizes, the accumulation of plastics on land and in the oceans is likely to accelerate, and the garbage patch twice the size of Texas in the Pacific Ocean will continue to grow unless the problem is addressed by government and industry and by the polymer chemists, physicists, and engineers themselves. Thus, in my opinion, the promise of polymers remains unfulfilled.