A UA team has discovered a simple process for making a lightweight plastic from the abundant element sulfur.

In the not-too-distant future, a new type of plastic invented at the University of Arizona might help your car drive itself and, when you arrive at the supermarket, help you pick out a ripe tomato.

Jeffrey Pyun, professor in the UA’s Department of Chemistry and Biochemistry, led research to develop a new class of inexpensive, sulfur-based polymer, or plastic, with properties that uniquely suit them for use in lenses in infrared devices like heat-sensing cameras.

The invention is the result of a cross-campus collaboration between Pyun, UA optical sciences professor Robert Norwood and UA chemistry and biochem professor Richard Glass.

Pyun, who joined the UA in 2004, discovered the new type of plastic as part of research on sulfur-based materials for advanced batteries he started in 2010.

The new hybrid material is known as CHIPs, which stands for Chalcogenide Hybrid Inorganic/organic Polymers.

Besides semiconductor properties useful for batteries, Pyun found that the new polymer had exciting optical properties in the non-visible infrared wavelengths — the part of the electromagnetic spectrum detected by heat-sensing thermal cameras and used by devices such as remote controls and automobile sensors.

In 2010, Pyun and his colleagues were focused on using waste sulfur from petroleum refining industry as low-cost feedstock for a new kind of plastic.

“Our thought back then was, how do we take this and directly, or in a single or convenient step, make it into a useful plastic?” Pyun said.

Besides its potential use as a semiconductor in batteries, Pyun’s group found that the new material had a very high “refractive index” — essentially a measure of how light bends as it passes through a material.

High refractive index materials allow opticians to make thinner eyeglass lenses and also helps lenses on infrared devices “see” more infrared radiation.

Typically, lens materials for infrared imaging are made of germanium or chalcogenide glass, which contains elements that create a high refractive index but can be complex and costly to produce.

On the other hand, sulfur is cheap and abundant as a refining byproduct and is very simple to turn into plastics.

“Sulfur you can get for the same magnitude of cost as coal, so it’s literally dirt cheap,” Pyun said.

There could be a big market for the new plastic in lenses used for industrial infrared applications ranging from missile target seekers, night-vision equipment and infrared detectors used in self-driving vehicles.

The material could someday be used with smartphones to create heat-sensing apps, such as an app that could detect the higher heat signature of a ripe fruit versus an unripe one.

“We have basically opened up an enormous new world for plastics in this already-established area,” Pyun said. “We are the first, and that’s why it’s so exciting.”

With the help of Tech Launch Arizona and Paul Eynott, TLA licensing manager for the College of Science, Pyun and his colleagues are starting to court industrial partners that could license the technology and start incorporating it into products.

Pyun has also set up a startup company, Innovative Energetics, to further develop commercial technologies.

Though the sulfur-based polymers could be used for a myriad of plastics applications, infrared optics is the main focus now, Pyun said.

The UA has filed more than 40 separate provisional patents surrounding the technology and has two issue patents, Pyun said.

“It’s a UA product. I’ve been here my entire academic career, and we made it happen really through grassroots efforts, support from the university, our extensive collaborations and international collaborations,” he said.

Beyond the UA, Pyun’s group has collaborated on the research with scientists at South Korea’s Seoul National University, including chemistry professor Kookheon Char.


Tech Launch Arizona has launched a series of podcasts about promising UA technologies, starting with an interview with Pyun.

The podcasts can be accessed at TLA’s website, techlaunch.arizona.edu, or on YouTube (tucne.ws/techlaunch).

Contact senior reporter David Wichner at dwichner@tucson.com or 573-4181. On Twitter: @dwichner

Senior reporter covering business and technology for the Arizona Daily Star/Tucson.com