Student turns discarded wood into insulation for beverage coolers

On a hot summer day, when most of his peers grabbed a drink from the cooler and moved on, Quazeem Tiamiyu paused to think about what’s underneath. That very thought led this University of Maine student to develop something extraordinary: a safe alternative to the toxic conventional insulation used in beverage coolers. And he built it from something you might find at a lumber mill. Conventional coolers use polyurethane foam. For manufacturers, injecting liquid foam into moulds is cheap and efficient, which is why the industry standardised on it decades ago. But this foam is made from raw chemicals that are hazardous to handle before processing. The chemicals are highly toxic and carcinogenic. Workers who handle them report respiratory disease and skin irritation. Once in landfills and waterways, polyurethane degrades slowly and pollutes the environment. It is non-renewable, which means it is made from fossil fuels rather than regrown resources. Most of us hardly realise this when we grab a drink. But Quazeem Tiamiyu did. So he made safe insulation using wood fibre foam, a bio-based insulation component that performs well. “Polyurethane foam’s raw chemicals are highly toxic and carcinogenic. For people who work with it, it has also been reported to cause respiratory disease and skin irritation,” Tiamiyu, a master’s student in the School of Forest Resources and a graduate research assistant in the Laboratory of Renewable Nanomaterials, said in a statement. He earned his bachelor’s degree from the Federal University of Technology in Minna, Nigeria. Tiamiyu joined the research group of Mehdi Tajvidi, a professor of renewable nanomaterials, to develop an environmentally friendly alternative to polyurethane insulation. Along with his colleagues, he designed a foam from cellulose nanofibrils, wood fibre, finely ground wood flour, and a surfactant that enables high foam volume. The cellulose nanofibrils are made by breaking down wood pulp into thin strands that are thinner than a human hair. Acting as a binder and stabiliser, the nanofibrils create web-like structures that hold everything together, turning materials that might otherwise end up as lumber mill waste into functional insulation. Tiamiyu mixes the ingredients in a blender, pours the slurry into moulds shaped like actual cooler inserts, drains the water, and dries the finished foam before encasing it in a plastic shell. He tested his foam against polyurethane and found that the results were nearly identical. “For the thermal conductivity, we are close. We actually found that we can compete with polyurethane foam. They have similar insulation properties,” he said. But this project has its limits. Polyurethane’s advantage is not just thermal performance, but manufacturing speed. Conventional coolers get their foam through a liquid injection process that happens during assembly. Tiamiyu’s foam requires a wet process, drying, and then encapsulation or fitting into the cooler cavity. Each step adds cost and complexity for manufacturers, who are already used to a streamlined system. Tiamiyu and his team are working on making the foam durable enough for daily use. At present, if the foam is crushed or damaged, its insulating ability decreases. They plan to conduct ice-retention tests to see how long the foam keeps ice compared with conventional coolers. “Usually, when you process cellulose nanofibrils, they tend to lose their nanoscale properties to be bound again, so another one of our future objectives is to see if it’s possible to disperse the ready foam in water and then mould it again into whatever shapes are possible,” Tiamiyu said. “If that is possible, the ready foam can be shipped and manufacturers can put it in water and mould it however they want,” he said. Though there are challenges, the researchers are hopeful that they will be able to use renewable materials in the future.