Roberto Uribe-Rendon

How electron beams improve materials

Just the word “radiation” is enough to conjure images of cancer patients or victims of plutonium exposure. 

For Kent State Physics Professor Roberto Uribe-Rendon, though, radiation is a way to improve our lives by improving the materials we use every day. 

Uribe-Rendon’s work focuses on using electron beams of high energy to achieve physical and chemical changes in different types of materials like polymers, composites and even biological materials.

This can result in everything from polymers with improved mechanical properties to the elimination of deadly pathogens in food products.

“We are trying to educate people about the use of radiation to modify the properties of materials, and improve their usefulness,” he said.

In polymer materials, Uribe-Rendon’s team is studying the use of electron beams in cross-linking polyethylene chains.

Cross-linking is the process of creating chemical bonds between the chains of adjacent polymer molecules. The process can be done through regular chemistry with the use of a catalyzer, but Uribe-Rendon said that leaves a contaminant that needs to be removed afterward.

“With the use of electron beams, you don’t have that problem, because the energy beam is the catalyzer,” he said.

With composite materials, electron beams can be used to combine glass and plastic fibers that have the lightness of polymers and the strength of metals. Such materials are used in manufacturing car body panels, for example.

Applying an energy beam to biological materials can help to eliminate contaminants in food, killing bacterial, viral, and fungal pathogens.

This process has already been in use since the early 2000’s by the federal government, Uribe-Rendon said.

Following the 2001 anthrax scare after 9/11, Congress and the White House began using electron beams to sterilize all mail entering those buildings.

In 2007, Kent State student Shannon Helfinstein earned her Ph.D by determining the proper dose of electrons necessary to kill anthrax contained in paper envelopes.

Dosage is an important factor in any electron beam manipulation of materials, Uribe-Rendon said.

In some situations, only the surface of the material may need to be treated, such as eyeglass lenses which have a coating applied to them to reflect ultraviolet rays. In other cases, the material may simply be extremely thin, like with nanomaterials, in which case low energy beams are more useful.

The university recently acquired a new piece of equipment, called an E-Beam System, which Uribe-Rendon said allows researchers that capability.

“It can be used for research, and we can also use it to teach students, and create courses based around it,” he said.