From the Times Record: Students, Businesses ‘Bond’ Over Composites
Article republished with permission from the Times Record
BY JT LEONARD Times Record Staff
Local students and businesses are working together to test a new form of polymer resin to see if it might be a “green” replacement for more hazardous traditional bonded composites.
The effort combines students and faculty from engineering departments at Southern Maine Community College’s Brunswick Landing campus and University of Maine at Orono, as well as fabrication shops such as Harbor Technologies in Brunswick and Kenway Corp. in Augusta.
Small-sample chemical testing was done at SMCC-Brunswick’s lab, while mechanical testing of larger, completed pieces was done in Orono.
Actual “real-world” evaluation is under way at Harbor Technologies and Kenway, according to Andy Schoenberg, director of SMCC’s composites engineering program.
Their common goal is to find a way to make polymer resins — the liquid plastic glue that holds composite layers together — work better, while also making them less hazardous to the laborers who apply them.
One way is to reduce the amount of styrene in the polymer resin.
Styrene is an organic compound added to resins to make them flow more smoothly and perform with predictable consistency as a bonding agent. It’s the ingredient that gives off the sweet, acrid, chemical smell most commonly associated with fiberglass construction.
It is effective, cheap to make and cheap to use — and, over time, it’s toxic.
The federal Evironmental Protection Agency lists styrene as a carcinogen and warns that long-term or concentrated exposure can cause respiratory problems, cancer and other health risks.
The problem, Schoenberg says, is finding a substitute ingredient that behaves like styrene but without the many health and environmental drawbacks.
He calls it “off-set chemistry.”
“We’re not replacing styrene yet, only reducing it,” Schoenberg said.
Drexel University and the U.S. Army Research Laboratory worked together to develop a modified resin with dramatically lower styrene content. That formula now is produced by several resin manufacturers, including Dixie Chemicals in Pasadena, Texas, which delivered a recent batch to Harbor Technologies in Brunswick.
The question is whether the lower-styrene resin, which contains methacrylated fatty acids, or MFA, will carry the same strength and elasticity properties as the formula it is intended to replace.
Harbor Technologies makes large, lightweight composite structures — filled with concrete and reinforced with steel cables — for use in pier and bridge construction projects around the world. The fabricator draped off a section of its shop, where Schoenberg and his students performed MFA absorption and flow-rate testing.
“We have to understand the science (of new materials) before we can figure out how they will perform in actual production,” said Rob Fuller, Harbor Tech’s chief operating officer. “Part of what SMCC was doing was figuring out how and why conventional testing methods don’t work anymore.”
Part of what SMCC’s students determined was that traditional testing methods, which are based on water and its properties, don’t necessarily apply to modern materials such as plastics. Essentially, the school’s Composites Engineering students are writing the testing and evaluation instructional manual as they go.
The program’s initial class had 10 students. Now in its second year, enrollment has doubled to 20. Some of them are older, nontraditional students who already have industrial experience; others are younger and training for advanced research positions.
Many already hold jobs with local companies, earning on-the-job experience while they complete their academic requirements.
All of the molecular-level testing and hypothesizing was done in SMCC’s lab which, for its relative size, is the most advanced facility north of Boston.
“We’ve done all of the small sample testing, now it’s in the Beta testing phase, which is a full-product evaluation,” Schoenberg said.
All composites use some kind of resin plus an added hardening agent, called a catalyst, to produce its trademark high strength-to-weight ratio.
Maine’s fiberglass boatbuilding industry may be the most well-known local example of composite engineering: Several layers of fibrous woven material are stacked together and soaked in plastic resin, which bonds the layers together to produce a strong, lightweight material.
But boatbuilding is only one example of five main areas of composite use. Others are construction, aerospace, alternative energy and consumer products.
New components are just the first part of the solution. The secondary concern is perception, and many people and businesses are reluctant to change traditional ways of doing business.
“The composite industry in Maine is still mostly a ‘mom and pop shop’ operation, so how do you get them the information they need to make a change?” Schoenberg said.
When large shops like Harbor Tech and Kenway begin using new materials, it’s like a vote of confidence that smaller shops pay attention to, he said.
There are drawbacks, however.
Right now, MFA resin costs about twice what conventional resin does. And there are other replacement chemistries being developed that may prove more or less effective than MFA or conventional resin.
At the moment, however, MFA’s test results and performance characteristics are promising: MFA resin flows more quickly and saturates some laminate materials better than conventional resin, which should translate to fewer barrels of resin needed to complete the same amount of production.