Fibre recovery
It is an opportunity to use these fibres in new composites and provide a solution to this pre-consumer and post-consumer waste.
Composite materials are made up of two or more components and the final materials have properties that are superior to those of the individual components. The main components are the polymer matrix and reinforcement. The matrix shapes the part’s geometry and provides cohesion while the reinforcement provides rigidity and strength.
In many cases, recycling composites has focused on mechanical recycling to recover the filler from the overall composite, despite the low added value. However, recovery of pure fibres for reuse in new composites is now an option of real interest because these fibres have a lower carbon footprint compared to the corresponding virgin fibres. This option also provides a clear solution to this form of pre-consumer and post-consumer waste.
How are these fibres recovered?
It is possible to recover fibres (mainly carbon and glass) using chemical recycling processes. Solvolysis processes (including glycolysis and acidolysis) and thermolysis processes (such as pyrolysis) help break the polymeric chains that accompany the fibre so it can be released, recovered and reintroduced in the market as a recycled material.
After the chemical recycling process, the recovered fibre must be treated using spin finish processes so it can be used again as a recycled raw material. This maintains the length of the fibre, which retains good fibre strength and therefore gives good properties to the final product. The spin finish process improves the bonding of the two elements (matrix and fibre) and reduces the two-phase effect to provide good final properties.
Chemical recycling of composites can also be used to obtain products such as monomers, oligomers and other chemicals from the polymer matrix and resin. These products can be recovered and brought to market as recycled raw materials for the chemical and polymer industries.
Posteriormente al proceso de reciclado químico, la fibra recuperada debe ser tratada mediante procesos de ensimaje para ser empleada otra vez como materia prima reciclada, manteniendo la longitud de la fibra, lo que mantiene una buena resistencia de la misma y por tanto dando buenas propiedades al producto final. El proceso de ensimaje mejora la unión de los dos elementos (matriz y fibra) y disminuye el efecto de dos fases, dando unas buenas propiedades finales.
En el reciclado químico de los composites, también se pueden obtener productos como monómeros, oligómeros u otras sustancias químicas de la matriz polimérica o resina. Estos productos son aprovechados e introducidos en el mercado como materia prima reciclada en la industria química o en la de polímeros, según los casos.
