Apply ligninases to resolve end-of-life issues of thermoset composite plastics
Thermoset composites – basically fibre-reinforced plastics – are increasingly popular as a construction material, replacing metals in many areas. In applications such as aviation and transport, where lower weight without compromising strength is important, they are becoming the material of choice; they are strong, light, generally heat-resistant and easy to shape. However, recycling these materials is a challenge; the chemical process that creates the composites and incorporates the fibres is irreversible. Currently, most of them are incinerated or sent to landfill.
There are already substantial amounts of these materials to be dealt with – in Europe alone, more than 40,000 tonnes of composite waste are deposited in landfills annually. However, with more than 12,000 aircraft approaching retirement – a process being accelerated by the COVID-19 pandemic – there will be a massive increase in these materials to be disposed of (aircraft are routinely 50-70 % composite). In addition, there are many other sectors – rail, construction, energy, automotive and electronics – that will also contribute with substantial quantities of composites. Clearly, another solution is required to address this challenge.
The BIZENTE project will demonstrate the potential of ligninase enzymes in addressing the disposal of these thermoset compounds to resolve the end-of-life issues of thermoset composites waste. In addition, it will help remove non-biodegradable thermoset composites from other environmental settings such as aircraft boneyards. This enzymatic process will valorise these waste streams by converting them into new feedstocks.
The overarching objective of the BIZENTE project is to demonstrate an effective way of dealing with the increasing levels of thermoset composites reaching end-of-life, avoiding incineration or landfill. Within this, the project has a number of specific objectives. These are to:
- Demonstrate the potential of three groups of ligninase enzymes to resolve end-of-life issues of thermoset composites, by developing an enzymatic biodegradation technology. This will involve mechanical and chemical pre-treatments to accelerate the action of the enzymes.
- Demonstrate the potential of developed enzymatic technology – once proved successfully at laboratory level – in a semi-industrial pilot environment. This will see the technology readiness level raised and will pursue higher rates of degradation or composite digestion, with an increase in the amounts of new monomers and by-products recovered.
- Establish a new value chain for products recovered after biodegradation; the monomers and by-products will be valorised as new feedstock for industrial applications, including in new thermoset resins. This will create a circular chain for what was a challenging aspect of waste management.
By achieving its overall objectives, the BIZENTE project will seek to treat and subsequently valorise thermoset composites, which are currently an increasing challenge for waste management. In addition to this, it will also make contributions to specific BBI JU KPIs through:
- Creating at least two new cross-sector interconnections. These will be between the waste management and biotechnological sectors and between the thermoset composite sector and the biotechnological sector. It will also reinforce a number of other cross-section interconnections, such as the industrial partners and the biotechnological sector.
- Establishing a new value chain – the 'enzymatic circular value chain for composite materials'. This connects four established value chains – chemical, composites, waste management and biotechnological – and closes the loop for composites waste management.
- Validating a new and improved processing technology – namely enzymatic degradation process for thermoset composites – and an increased technology readiness level.
- Creating new bio-based building blocks as a result of the process that will deliver at least three new monomers. These can be valorised in the polymerisation of new thermoset resins.
In addition, the BIZENTE project will bring specific environmental benefits. By rendering thermoset composites suitable for degradation, it will increase the range of feedstock that can be sustainably processed through biocatalytic systems. It will also decrease, by at least 40 %, the current amount of non-biodegradable polymers sent to landfill or for incineration.