What is Irradiation Processing?  Return to top
The use of irradiation as a major industrial processing tool began more than 30 years ago. Spurred by solid-state electronics and innovative wire, cable, and heat-shrink applications, the UV/EB industry has grown to become an international multi-billion dollar per year industry. Today, ultra-violet curing has become commonplace while electron beam systems are replacing traditional chemical sterilization methods in the medical supply industry. At the same time, electron accelerators have become workhorse tools for tire manufacturers and plastics processors, as well as for companies in the gemstone industry.

Irradiation is a very powerful form of high-energy radiation processing, which when properly used, produces profound effects in materials. These effects cannot be produced in any other way and offer efficiencies that help keep the unit cost of treatment exceptionally low. Irradiation can sterilize fully packaged and sealed medical supplies at room temperature (particularly important for plastic, single-use products), cure rubbers and plastics with an “on-off” control unattainable with conventional chemical techniques, and cure solvent-less paints and coatings with unmatched speed. In all cases, the highly directed radiation beam and computer control make the technology an energy-efficient, fast, and versatile industrial manufacturing alternative to conventional processing. Although well established in the plastics industry, this technology is in various stages of development for a variety of other applications, such as electronic components, water stream treatment, weapons destruction, and biomaterials.

It’s important to note that the products and materials irradiated by ETC’s electron accelerators for the production of industrial products WILL NOT BECOME RADIOACTIVE! ETC uses electron accelerator systems that can be switched off, thereby immediately eliminating all radiation.

How Can Irradiation Processing Improve Materials? Return to top
During the irradiation process, the energy from the radiation source is transferred to the processed material. This results in a variety of chemical reactions that alter the molecular structure of the material. There are five fundamentals:

• Cross-linking of polymers, where a network of polymer chains are joined.
• Degrading of polymers, where the molecular weight of the product is reduced through chain scissioning.
• Grafting onto polymers, where a different monomer is produced and grafted onto a polymer chain.
• Polymerizing (curing) of monomers and oligomers by irradiation. Irradiation curing (as in the case of coatings) is a combination of radiation polymerization and cross-linking.
• Modifying crystal lattice for semiconductors and gemstones.

Careful selection of irradiation processing conditions can result in improvements of material properties, including mechanical properties, thermal properties, chemical resistance, particle size, melt properties, material compatibility, surface properties, and other characteristics.

What Are The Benefits of Irradiation-Treated Products? Return to top
Using the electron beam in industrial applications has many benefits. Cross-linking changes thermoplastic materials into thermosets and cures rubber. In addition, the molecules within the material are changed and tend to move rather freely. As temperature rises, uncross-linked materials soften and eventually melt. When they are irradiated, the molecules are cross-linked. In other words, they slow down, become more resistant to heat, and lock together to form more stable bonds.

Benefits of this crosslinking include:

• Increased material strength
• Increased material stability
• Resistance to deformation
• Resistance to chemical solvents
• Shrink memory
• More stress cracking resistance

In terms of biological benefits, the benefits are numerous. With respect to foodstuff, the benefits include the disinfestation or elimination of insects from grain, tobacco, and other unprocessed bulk crops. The second benefit involves the complete sterilization of medical products and aseptic packaging of materials for foods. In other words, the electron beam can be used to sterilize medical equipment and food packaging.

Accelerators Return to top
The ETC facility has two accelerators that are capable of producing small-to-medium e-beam streams.