Prof. Geoff Coates, chemistry and chemical biology, likes to save the orange peels from his lunch. He saves them, takes them to his lab and gently sprinkles his “zinc-based pixie dust” over his recycled waste to create a truly magical substance — a biodegradable plastic composed of carbon dioxide and citrus chemicals.

Plastic materials remain ubiquitous throughout the world, but the production of plastics harms the environment and consumers. In response, Coates and his team continue to improve plastic production by designing “green polymers,” or biodegradable, non-toxic plastics created from cheap resources found at any local garbage dump.

“We’re trying to convert cheap, non-toxic resources into important polymers,” Coates explained. His goals include utilizing cheap, renewable resources, creating safe, benign plastics and improving efficiency in high-quality plastic production.

Industrial producers of most plastics consume non-renewable fossil fuels. These scarce resources are also expensive.

“If you can get away from oil as a source of polymers, it’s an important environmental goal,” Coates said.

Instead, Coates creates plastics from certain primary ingredients: gaseous carbon dioxide, various chemicals including epoxides, lactic acid and turpenes. A handy chemist can find lactic acid and turpenes in foods like milk and citrus.Prof. Geoff Coates

“When you peel an orange and the room smells like citrus, that’s the chemical,” Coates said. His research involves recycling these organic precursors and building complex polycarbonates. Specifically, Coates developed a catalyst that converts the turpenes of orange peels into a type of Styrofoam.

Coates and his team discovered a group of zinc-based catalysts, which Coates affectionately calls, “zinc-based pixie dust.” This pixie dust greatly increases the rate of the reaction between carbon dioxide and various epoxides, allowing a lengthy reaction to occur in a short period of time.

Using these practical monomers lessens the environmental footprint of non-biodegradable plastics. The renewable resources form less stable polymers which, under the appropriate conditions of temperature, moisture and acidity, readily decompose back into the original monomers.

Tiny bacteria decompose the polymers, breaking the bonds of these complex molecules. Depending on the surface area and volume of the polymer, oil-based plastics require hundreds of years to decompose due to extremely strong bonds. On the contrary, according to Coates, under optimal conditions, his green polymers decompose within several months, hastening the recycling process.

The green polymers are safer than certain plastics like Nalgene.

According to Coates, “There is some evidence that the plastics have chemicals that are gene disrupters.”

In 2003, geneticists at Case Western University examined the presence of bisphenol A, a known artificial estrogen found in Nalgene plastics such as water bottles and baby bottles. The team discovered that although the plastic bottles maintained their structure, they released small quantities of bisphenol A into the water. The team found that the estrogen interfered with the reproductive cycles of common lab mice, causing various instances of mutation and hyperploidy.

Many types of non-biodegradable plastics contain bisphenol A. These range from the water bottles of the lab mice to Tupperware containers in many refrigerators. Evidence suggests that the estrogen causes genetic disorders and breast cancer in humans. However, because Coates’s plastics rely entirely upon non-toxic monomers they provide a safe alternative.

The construction of such alternatives, however, relies on the development of feasible chemical reactions. Monomers like carbon dioxide are plentiful, but exhibit relatively no reactivity, so better catalysts are needed.

With his polymer producing pixie-dust, Coates co-founded the company Novomer, which announced in July the production of NB-180 — a green polymer that forms a type of binder used in the electronic manufacturing of fuel cells, solar cells, nanotechnology, microelectronics and semiconductors. The binder burns at lower temperatures and decomposes safely, fulfilling Coates’s goal of a cheap, non-toxic and effective product to replace harmful plastics. Novomer has been recognized for its innovative environmental practices.