Recycling and Reprocessing of Flax/Acrylic Biocomposites: A Dissolution Method Using Acetone as Solvent and Water as Non-Solvent

Abstract

This study explores the second-generation biocomposites utilising flax fabric reinforcement with liquid thermoplastic Elium® (acrylic) resin. The surface tension and wettability of the liquid acrylic resin with flax fabric were characterised through experimental techniques. Subsequent manufacturing of second-generation flax fibre/Elium® laminates involved distinct reprocessing routes incorporating varying levels of reclaimed materials, with the natural fibre pre-form preserved and reused. A dissolution process using acetone as solvent and water as non-solvent enabled recovery of the acrylic polymer matrix. The residual polymer remaining on the flax fibres after dissolution served as a sizing agent in the second-generation laminates, resulting in improved interfacial bonding. After normalisation to a common fibre volume fraction, the second-generation infused laminate demonstrated a 6.5% increase in flexural strength, a 16% increase in flexural modulus, and an 11.4% increase in short beam strength compared to its virgin counterpart. Molecular simulations further elucidated the interactions between flax fibre, acrylic monomer, and acrylic polymer. These findings demonstrate a viable pathway for the production of circular acrylic matrix based thermoplastic biocomposites with significant industrial potential.