Styrofoam, a Practical and Problematic Creation

The good and bad of an everlasting invention.

By Clay Cansler | July 31, 2018

A woman holds a Styrofoam “log” in this 1949 photo from the Science History Institute’s collections.

Science History Institute

Dow invented Styrofoam in 1941, rediscovering a process first patented by Swedish inventor Carl Munters. Dow bought the rights to Munters’s method and began producing a lightweight, water-resistant, and buoyant material that seemed perfectly suited for building docks and watercraft and for insulating homes, offices, and chicken sheds. These days Styrofoam is used for building insulation known as blueboard and for craftwork, such as the green foam blocks used by florists in flower arrangements.

Although Styrofoam has become a catchall for the coffee cups, packing peanuts, and many other nondescript items made of polystyrene foam, proper Styrofoam is a little different. Produced through extrusion, it is stronger, stiffer, and more expensive than the stuff used to make plates and cups. Those items are made through an expansion process in which small beads of resin are warmed and then squeezed together into the desired shape. This expansion-based cousin arrived in the 1950s and over time has been adopted for countless applications because of its properties—tough but virtually weightless, inexpensive, sterile, and chemically stable.

But polystyrene foam has its problems. Initially, ozone-depleting chlorofluorocarbons were used to expand the polystyrene beads into foam, until alarm rose over the growing hole in the ozone layer. The CFCs were eventually replaced with less harmful gases, but that wasn’t the end of the environmental concerns. The foam’s base material, styrene monomer, is a carcinogen; plastic- and rubber-industry workers exposed to the unreacted monomer suffer higher rates of some types of cancer. Even more problematic, the finished material can take thousands of years, and perhaps more, to biodegrade. From 2002 to 2015 about 316 million metric tons of polystyrene were produced globally, with more than half thrown out inside of a year. And that doesn’t include the many other types of plastics that get tossed—an estimated 302 million tons worth in 2015 alone—all adding up to an enormous litter problem that particularly affects the oceans, where the materials accumulate, and sea life, which consume the floating bits and pieces. In response—and in the absence of a viable recycling method—New York City, Los Angeles, Washington, D.C., and many other municipalities in the United States have banned single-use polystyrene containers.

As for all the polystyrene foam already floating around, scientists have investigated some novel solutions. An experiment published in 2006 suggested that after superheating the stuff into styrene oil, a strain of Pseudomonas putida, a type of soil bacteria, could convert the oil into a biodegradable form of plastic—polyhydroxyalkanoate, or PHA. Unfortunately, the process consumes a lot of energy and produces toxic by-products, such as toluene. Perhaps more promising, in 2015 a group of Chinese researchers published a report showing mealworms can survive on a diet of polystyrene foam as successfully as those fed a typical diet of bran. And in 2017 a team of European scientists found that waxworms had a similar appetite for polyethylene plastic bags. Is it possible we (or rather our larval friends) could eat our way out of our garbage problem?