Within the research activities of BIZENTE are those related to customisation and development of enzymes and resins at lab level. In this respect, the consortium has been working on the chemical modification of resins to enhance materials biodegradability. Below we offer a summary of the main findings of this work.
Unlike thermoplastic for which effective recycling options do exist, thermoset composites cannot be melted because they contain, in their structure, crosslinked polymer networks based on irreversible chemical bonds. Therefore, currently most of the thermoset composites waste are not properly recycled and they are either incinerated or diverted to landfill. Industrial needs for high performance materials have increased the use of composite materials, so there is a need to develop and ensure a systematic circular ecosystem for these materials as a priority in Europe.
In that respect, the objective of BIZENTE project is to develop a multi-step degradation process to degrade crosslinked thermoset materials when they reach their end-of-life. This multi-step degradation process is mainly based on enzymatic degradation process combined with appropriate set of chemical and mechanical pre-treatments. In the scope of BIZENTE project, research is currently on-going and the project’s partners are working in parallel in order to:
- Develop custom designed enzymes on the basis of reference resin model molecules.
- Achieve chemical modification of currently used non-recyclable resins in order to favor enzymatic degradation.
- Achieve mechanical pre-treatment to facilitate both chemical and enzymatic degradation processes.
Within the project, SPECIFIC POLYMERS is in charge of developing and implementing chemical modifications to the resin in order to ease their biodegradation.
Main chemical modifications are based on Covalent Adaptable Network (CAN) technology in which reversible bonds can be broken under a given stimuli. Inserting such bonds into the crosslinked network and mastering the corresponding reversibility offer the possibility break the network down and recover a full or partial solubility that would favor the enzymatic degradation process. In addition to this main strategy, increasing the content of biodegradable moieties within the network is also targeted since it can influence the efficiency of the biodegradation process.
All performed modification are made to favor of the recyclability of the materials but without impacting they other key specifications. Indeed, it is important that the main properties of the resin developed in the project remain consistent with the implementation processes and the final applications’ requirements of the end-users.
In the scope of BIZENTE project, 4 different reference resins characterized by different chemical natures (epoxy, vinyl ester, unsaturated polyester) and different process and applicative specifications are targeted and chemical modification approaches are tuned accordingly.
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