Rider and his team hope to create a resin system that avoids specific monomers, namely formaldehyde and phenol. In addition, they want to frame a solution that has the least impact on Zodiac’s current manufacturing stream. “We don’t want the company to decommission equipment,” says Rider. “We want them to make use of processing techniques and solvents they already have in place.” Zodiac Cabin & Structures uses compression molding to fabricate parts.
WWU began its quest for an alternative resin with a bismaleimide polymer, which is mechanically robust and high modulus and has a high glass transition. The team has found a way to improve the thermal robustness – how much of the material can be retained at high temperatures – with an additive that is very low in concentration. Rider says .5 percent loading can increase the weight retention by approximately 10 percent. “While that might sound like an incremental improvement, when you talk about decreasing smoke in the event of a fire – or avoiding fire altogether – the weight loss at a high temperature that we have measured here is exciting,” says Rider.
Researchers are now trying to move from a lab-scale sample to composite production. The next step is to create an intermediate-scale replication (approximately one-tenth the size) of Zodiac Cabin & Structures’ manufacturing facility at WWU. They will make fiberglass prepregs using equipment donated by the company. Once that is successful, the research team will subject the composites to the Federal Aviation Administration’s smoke density and flame resistance tests. Rider and the students will see how their composites fare compared to ones using phenolic resins.
Eventually the researchers would like to make the processing techniques as green as possible, using water as a solvent – or even avoiding water usage altogether with eutectic solvents. (A mix of substances that melts at a single temperature that is lower than the melting point of any of its separate constituents.) In the meantime, Zodiac and its resin supplier Georgia-Pacific Chemicals are happy with the partnership between industry and academia. It holds promise not only for those two companies, but for others throughout the composites industry as well.