There's a lot of issues which hinders the rate at which we're able to recycle composite materials, these include technological, economical, and the difficulty of separating homogeneous particles from composite materials.

With all these challenges, researches have been done in this sector in an attempt to improve upon existing techniques which exists today. Some of these techniques are in the categories of mechanical, thermal and chemical recycling, which are yet to gain widespread adoption.

A few of the reasons why these techniques are unable to gain widespread adoption is because it's either too energy intensive, produces low quality outputs or creates unmanageable chemical wastes and pollution which would later cause harm to the environment.

To further understand why there's a lack of widespread attention given to composite materials, we also need to remember that for a waste type to be commercial viable, there needs to be enough volume (waste-wise) in the market. Which is false when compared to waste types such as plastic, metal, glass and paper.

The biggest markets which utilise composite materials include Automobiles, Aerospace and civil engineering, and the lifespan produced in these industries for example aerospace (where planes can easily last for several decades), and many of the other industries, can at some be very lengthy before wastes are ready to be recycled.

Global composites market share figure
Global composites market share figure — Figure 1

Though, when added with off-cuts during the production stages of composite materials, the need to provide better recycling methods that can produce high quality outputs, further increases.

One of the easiest ways to tackle economic factors which hinders R&D for better recycling methods, sounds like a no-brainer, but its to make and use composites which are easier to recycle in the first place—Lowering the barrier for entry, increase widespread adoption.

Simplifying the recycling process for composite is very important. Its estimated that by 2023 an average of 1000 aircraft should be retiring year-on-year. This not only brings a lot of supply to the market, but it also makes it imperative for unified composite recycling methods to be developed, in order to take advantage of the materials which can be harvested from these aircraft in order to fill the growing demand which exists in the marketplace.

An organization that should gain widespread recognition, and praise, AFRA, which was incorporated in 2006 by Boeing and 10 other aircraft manufacturers with a common interest in improving the recycling processes used for retire aircraft’s. This allowed companies within Aerospace to share knowledge and use the latest recycling techniques available in the market in the market.

With the growing demand for aircraft composite materials and short supply, it makes sense, at least economically, to recycle composites in retired planes instead of using raw materials. Instead of leaving aeroplanes in aircraft graveyards/landfills, this allows the manufacturer to extract as much profit as possible whilst being environmentally friendly.

In Europe, the success of AFRA, encouraged companies such as Airbus, EADS, Suez-Sita, LIFE and the European Commission to initiate project PAMELA which demonstrated that more than 85% of the weight in an aircraft can be fully recycled, re-used or recovered.

Technological advancements

Another promising technological advancement, which hasn't been mentioned in this article is the use of oxygen in supercritical water.

As demonstrated by Yongping Bai, Zhi Wang and Liqun Feng in their research papers they were able to recover the carbon fibers in carbon fibers reinforced epoxy resin composites with minimal loss in tensile strength.

This brings new possibilities. For example, imagine being able to create new machine that are used during the production stages of composite materials added with stronger waste management and environmental legislations within the production stages.

I'm sure you know what this means. By developing and enforcing such technologies within the production stages of composite materials, the need to send off-cut composite wastes from the production stage would be curved. This means higher re-usability rates and significant decrease of composites materials being sent to landfills.

What to expect

In current times, the recycling of glass and metal is the case where recyclates can be added to the mixture to produce new products. This allows us to reduce the demand put on obtaining raw materials. Its absurd that the same method isn't used to produce composites.

You can expect a future where the market for composite recyclates has fully matured, with new product designs that are easier to recycle, that are much more tolerable to being mixed with recyclates and better separation technologies such as oxygen in supercritical water, described above.



Proposed Framework for End-of-life Aircraft Recycling

Recycling of composite materials

Chemical recycling of carbon fibers reinforced epoxy resin composites in oxygen in supercritical water