Professor looks to shake radiation’s ‘nasty’ reputation

The words ‘clean’ and ‘radiation’ rarely find a home in same sentence. But that’s not the case for Clara Wren. The Western Chemistry professor is working on a project she’s titled Radiation: Creative, Clean and Efficient Manufacturing Processes.

In what has been called a radical approach to radiation, Wren and her colleagues are testing various radiation-based environmental technologies to demonstrate radiation’s potential to strengthen, sanitize and change the chemical composition of materials used in the food industry, sterilization of medical supplies and aerospace, among other possible applications.

The possibilities are almost limitless for what radiation can improve, Wren said. Exposing metals to radiation through her method can help stop corrosion, strengthen polymers, sanitize medical devices and even reduce pathogens in our food.

While radiation can produce reactive, or ‘nasty,’ chemicals, irradiating (exposing something to radiation) through water makes radiation a ‘clean’ method to strengthen, sanitize and improve the quality of the materials exposed, Wren explained.

While irradiation is in progress, highly reactive radicals are present. Once irradiation stops, however, these radicals disappear, either reconstituting water or forming components of it.

“The nasty chemicals hang around only during irradiation. Once irradiation stops, they (the nasty chemicals) react with each other to form benign chemicals: hydrogen and oxygen, or (they) reform water. No chemical cleanup is required,” she added.

What’s more, since these cleaner byproducts are produced uniformly upon irradiation at room temperature, there are other advantages – for example, heating or thorough mixing of chemical reactants is not required to improve the chemical reaction efficiency.

“When you radiate, you break water molecules, and you have something else that can form something different,” Wren said.

In the case of using a byproduct for strengthening materials and preventing corrosion, she gave titanium as an example.

“Titanium is very strong, but the metal is very reactive. It’s not strong in terms of corrosion,” Wren said.

In its wide array of industrial uses, including medical, construction and aerospace industries, titanium alloys are used because they are stronger and less susceptible to corrosion. But radiating titanium can result in the formation of an oxide, which acts as a thin, insulating layer, protecting the metal against corrosion.

“Corrosion behaviour also depends on how oxidizing the water is. If you radiate in water, and water breaks down, some of these species can be very oxidizing and some reducing. If we understand the underlying process (of metal oxidization and water irradiation), then we can use radiation to protect corrosion behaviour,” Wren continued.

“When you radiate a composite material, it makes it stronger because it increases the close linking between molecules. When you radiate a golf ball, it bounces better for the same reason. When you radiate polymers, they change their characters,” she added.

Another potential use of radiation could help produce better quality health and beauty products. Radiation can be used to control the size of small colloid particles in, say, women’s foundation, making them smaller and a more consistent size. This foundation would make for a more flawless and consistent appearance when applied on the face, Wren explained, adding there are companies doing this with makeup, toothpaste, aerosols and other such products.

Wren, Natural Sciences and Engineering Research Council of Canada and Atomic Energy of Canada Ltd. Industrial Research chair at Western, is working with her research team to improve understanding of chemical and transport kinetics under the dynamic radiolysis conditions that can be used to develop safe, environmentally friendly, and novel technologies based on ionizing radiation.

This story originally appeared in the May 22, 2014 edition of Western News.