Carbon fiber is a manufacturing material being used more frequently to make consumer products. Once the domain of the aerospace industry, carbon fiber is attractive to product designers wanting something new. Still, some manufacturers rely on more traditional plastics when their products do not need the structural integrity that carbon fiber affords. Among the reasons for doing so is plastic’s more recyclable nature.
Recycling carbon fiber is comparatively harder. Therefore, a company that makes plastic shipping pallets might choose a traditional plastic material instead. Their design doesn’t require carbon fiber’s strength. And at the end of the day, a plastic pallet is more easily recycled than one made from carbon fiber.
We recycle plastic pallets, incidentally. Along with other types of commercial plastic waste, we collect pallets that can be easily reduced to plastic regrind. We then turn around and sell that regrind to manufacturers.
Carbon Fiber Is a Plastic
Some of the confusion surrounding carbon fiber recycling is due to a misunderstanding about the material itself. What we call carbon fiber is actually carbon fiber reinforced plastic (CFRP). As a plastic material, carbon fiber is essentially a thermoset resin structurally reinforced by carbon fiber embedded within it. It is really a reinforced plastic.
Carbon fiber sheets inside a CFRP building panel provides structural integrity the same way rebar does in a concrete design. Unfortunately, the very same material that makes a CFRP so much stronger also makes it much more difficult to recycle.
Not a Simple Grinding Job
We can turn everything from plastic pallets to unused plastic totes into a reusable material by grinding it up. What we do at Seraphim Plastics isn’t rocket science. It doesn’t require a tremendous amount of energy or scientific analysis. It does not require an extremely tight monitoring program with very low tolerances. Grinding commercial plastic waste into regrind is a very forgiving process.
The same is not true for carbon fiber reinforced plastics. Recycling them is not a simple grinding job. Some carbon fiber products can be ground and shredded, then added to a molten resin and formed into new products via a mold. But those products will never be as strong as virgin carbon fiber.
If you want to actually separate the carbon fibers from the resin in which they are embedded, you have to employ a high heat process that is incredibly energy heavy. Even at that, you risk damaging the fibers you are trying to recover. An alternative is to use a chemical solvent. Such solvents don’t require as much energy, but they are even more potentially harmful to carbon fibers.
Reinforcement Is the Problem
The simplest way to understand why carbon fiber is difficult to recycle is to compare carbon fibers to rebar. If you are breaking apart concrete columns, you can separate concrete from rebar with a minimal amount of effort. Concrete doesn’t tend to form a cohesive bond with rebar, so it will fall right off given enough force or pressure. Again, that is not the case with carbon fiber.
Fabricating a carbon fiber piece requires saturating a carbon fiber fabric with epoxy resin. When the entire assembly is cured in an autoclave, heat and pressure create a very strong bond between fabric and resin. It is a lot like a wine stain in a garment. The bond is so strong that breaking it is nearly impossible.
Carbon fiber can be recycled but doing so is expensive and time-consuming. On the other hand, recycling the commercial plastics that we buy is comparatively easy. That’s why so many companies like ours do it.