Kettering University professor involved in cutting-edge polymer technology

Like most inventors, Dr. Lars Beholz has used every available resource including the kitchen stove.

"I only gassed my wife and kids out of the house once," he proudly claims.

None the worse for wear, the family was able to return after only a few hours, and Beholz was one step closer to his breakthrough discovery of a new process for treating the surface of polymers (plastics) to make them paintable.

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This is an important technological breakthrough, especially for the automotive industry, which is increasingly reliant on using polymers in the production of vehicles. The two technologies currently used for painting auto parts made of polymers involve a blending process that compromises the structural integrity of materials and increases production costs, and a flame treatment which can be a safety hazard, said Beholz, a principal of Selective Technologies Inc. of Flint.

"What Dr. Beholz has done is make something that is totally inert and non-adhesive, glueable and paintable in an environmentally friendly and cost-effective way," said Dr. Carl Aronson, assistant professor of Chemistry at Kettering University.

In October of 2000, Beholz enlisted the help of Aronson to test the underlying chemistry of his project and scientifically explain the process he had developed.

"Inert substances are resistant to reaction, meaning they are difficult to chemically alter. Usually you have to do something harsh to them to effect a change," said Aronson.

With polymers this has included using strong acids, ultra violet radiation, toxic oxidants and open flame.

Image removed.Aronson, using analytical equipment at Kettering, was able to identify what happens to the surface of polymers chemically, as a result of Beholz's process, and adjust treatment conditions to optimize the reaction. His research was funded by a portion of his New Faculty Professional Development Grant from Kettering.

The process, developed and patented by Beholz, alters the surface structure of polymers chemically, making them sticky on a molecular level which allows them to be painted or glued depending on the application. It involves immersing or spraying the surface of a polymer with a water-based solution that includes a mild oxidizer (such as sodium hypochlorite) designed to react with a weak acid (dilute acetic acid or succinnic acid solution). This effects a controlled degradation of the oxidizer allowing the addition of chlorine to the polymer's surface making the surface receptive to paint or glue.

After extensive testing, it is thought the process works by forming free radicals that extract hydrogen atoms from the polymer chains on the surface of the plastic, enabling chlorine to react with the remaining carbon radicals rendering the surface adhesive. The process only effects change on the surface, but does not compromise the structural integrity of the bulk material.

This is good news for auto manufacturers looking for a way to apply paint to more mechanically strong, and cheaper, polymer components. Currently automakers have to use a blend of paintable (weaker) and more expensive polymers for parts like doors and bumpers.

In Europe, the process for painting polymer auto parts includes using a torch to apply direct flame to the polymer, and then painting the surface while it is still altered from the heat treatment. The United Auto Workers Union determined this method was too dangerous for use by its members.

The process developed by Beholz uses no organic solvents and the solution is easily handled before and after application since it is used at or below the boiling temperature of water.

"Kettering is on the cutting edge of polymer adhesive technology. It's very progressive of the university to be doing this type of research," said Beholz. "We've made a new discovery working in cooperation with Kettering, and are pursuing additional patents to further develop the technology."

Aronson sees the collaborative research as a boon for Kettering academically. "It gives us a chance to take our research to the next level," he said, "and transfer it to a one-of-a-kind educational opportunity by offering courses that bridge Chemistry with Mechanical Engineering in polymer surface adhesion technology."

"The technology area this encompasses aligns itself with companies Kettering is currently linked to through the university's professional cooperative education program. We will be able to give Kettering students something that can enhance their co-op experience," said Aronson.

This science has been accepted for presentation at the World Congress on Adhesion scheduled for February 2002 in Orlando, Florida. Aronson will present their research results at the Congress.

To further future research efforts, Aronson and other chemistry professors at Kettering have formed the Gemini Research Group. Through Gemini, Aronson and Beholz have applied for two Small Business Innovation Research (SBIR) grants from the U.S. Department of Defense. The grants are worth $100,000 each and are designed to encourage small businesses such at Selective Technologies, Inc., and academia to work together.

The grants are to implement the polymer painting technology on military vehicles. The U.S. Army wants a peelable paint while the Navy is looking for a permanent and robust adhesive for polymer based aircraft parts.

"It is anticipated that once the grants are received in December, Selective Technologies will need more co-op students and we would certainly look to Kettering first," said Beholz.