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.
Accordingly, the objective of BIZENTE project is to develop multi-step degradation process to degrade thermoset materials at their end-of-life. To do so, BIZENTE partners are working in parallel in order (i) to develop specific enzymes custom designed on the basis of reference resin and (ii) achieve chemical modification of the reference resins in order to favor enzymatic degradation. Indeed, due to the crosslinked nature of the thermoset reference materials, their direct degradation through enzymatic processes is unlikely to bring good results due to a lake of accessibility to the bulk of the material.
To figure out this issue, SPECIFIC POLYMERS is in charge within the project to propose, develop and implement chemical modification to the resin in order to ease the targeted biodegradation process. Since there are 4 different reference resins characterized by different chemical natures (epoxy, vinyl ester, unsaturated polyester) and different KPI (process and applicative specifications), the chemical modifications strategies targeted here were different in each cases
Currently, SP developed at least one promising formulation for each reference resin, the most advanced being performed to generate up to 1.8kg of modified resin. This resin was mechanically grinded, chemically pre-treated and the enzymatic degradation in still in progress.