Composite materials, known for their durability, high strength, excellent quality, low maintenance and low weight, are widely being used in automotive, construction, transport, aerospace and renewable energy industries. Their use in numerous engineering applications is a result of the edge composites provides over traditional materials. Recycling and disposal of composite materials is an issue that is being increasingly addressed, as it should with any widely used material.
Previously, there were very limited commercial recycling operations for main stream composite materials due to technological and economic constraints but R&D activities are on the rise.
Fiberglass is a versatile material that provides tangible potential over conventional materials such as wood, aluminum and steel. Fiberglass is produced by using less energy and is used in products which result in less carbon emissions. Fiberglass offers advantages of being light weight yet has high mechanical strength, impact resistant, is chemical, fire and corrosion resistant, and a good thermal and electrical insulator.
Even though fiberglass is extremely useful for the reasons previously listed, an "end of life solution" is needed. Current FRP composites with thermoset resins do not biodegrade. For many applications where fiberglass is used, this is a good thing. However, in landfills, this is not. For this reason, recent research and development has good into a solution.
Research has lead to methods such as grinding, incineration, and pyrolysis being used for recycling fiberglass. The recycled fiberglass finds its way in various industries and can be used in various end products. For instance, recycled fibers have been effective in reducing shrinkage in concrete thereby increasing its durability. This concrete can be used best in freezing temperate zones for concrete floors, pavements, sidewalks and curbs.
Other uses for recycled fiberglass include being used as a filler in resin, which can increase mechanical properties in certain applications. Recycled fiberglass has also found its use together with other products such as recycled tire products, plastic wood products, asphalt, roofing tar and cast polymer counter tops.
Recycling Carbon Fiber
Carbon fiber composite materials are ten times stronger than steel and eight times that of aluminum, along with being much lighter than both materials. Carbon fiber composites have found their way into the manufacturing of aircraft and spacecraft parts, automobile springs, golf club shafts, racing car bodies, fishing rods, and more.
With the current annual worldwide carbon fiber consumption being at 30,000 tonnes, most waste goes to the landfill. Research has been conducted to extract the high value carbon fiber from end-of-life components and from manufacturing scrap, with the goal to use them for creating other carbon fiber composites.
Recycled carbon fibers are used in bulk molding compounds for smaller, non load-bearing components, as a sheet-molding compound and as recycled materials in load bearing shell structures. The recycled carbon fiber is also finding uses in phone cases, laptop shells and even water bottle cages for bicycles.
Future of Recycling Composite Materials
Composite materials are preferred for many engineering applications because of its durability and superior strength. Proper waste disposal and recycling at the end of the useful life of composite materials is necessary. Many current and future waste management and environmental legislation will mandate engineering materials to be properly recovered and recycled, from products such as automobiles, wind turbines and aircraft that have lived their useful life.
Although many technologies have been developed such as mechanical recycling, thermal recycling and chemical recycling; they are on the brink of being fully commercialized. Extensive research and development is being done to develop better recyclable composites and recycling technologies for composite materials. This will contribute to the sustainable development of composites industry.