Researchers Developing Adhesive to Join Composites to Non-Composites

By Morgan Laidlaw

This week in adhesives news, researchers at Michigan State University are developing an advanced adhesive to join composite materials to non-composites. Mahmood Haq and his team at Michigan State University’s Composite Vehicle Research Center are developing new ways in which composites and traditional materials can be joined without compromising the desirable structural properties of the composites.

When joining a composite and a metal, manufacturers want to avoid drilling holes in the composite, according to Haq. “If you drill a hole with mechanical means, damage is introduced at the edges of the hole, and the layers that make up the composite separate,” said Haq. “You lose up to 60% of the capacity of the composite to carry load.”

Using an adhesive to bond the two together also has limitations since once the adhesive cures, the bond cannot easily be undone. Haq and his team are working on advanced adhesives with special properties that allow them to be taken apart, repaired, or healed. These special properties are obtained by adding electrically conductive nanoparticles to the adhesives. When activated with the right kind of electromagnetic radiation, the nanoparticles begin to vibrate and heat the adhesive.

“Millions of these nanoparticles are embedded in the adhesive,” said Haq. “By using what we call targeted heating we can bond them and reverse the bond and take them apart. Just the adhesive heats up without having to heat up the entire structure.”

The key to making this joining technique practical is to be sure it can be integrated into today’s auto assembly line practices. “We want joints that are easily and quickly produced,” said Haq. “We don’t want to have to totally re-tool the assembly lines. We don’t want to have to invent a new technology which disrupts current manufacturing practices.”

Read the full story here.