Co-authors​ :

 Arun Kumar ALAPATI (UNITED KINGDOM), Ankur BAJPAI (DENMARK), Conchúr M Ó BRÁDAIGH (UNITED KINGDOM), Colin ROBERT (UNITED KINGDOM) 

The current investigation involved the modification of a Bisphenol-A based epoxy resin, which was cured using a recyclable amine-based hardener Recyclamine® R501. The modification was achieved by including nanoscilica particles, namely Nanopox A510, which had a diameter of 20 nm. The dispersion quality of the nanoscilica particles in the epoxy matrix was examined using a transmission electron microscope (TEM). The resulting matrix was thoroughly and precisely characterised using standard techniques. This involved a comprehensive analysis of the thermal, mechanical, and fracture mechanical characteristics, providing extensive characterisation. The cured epoxy polymer exhibited a glass transition temperature (Tg) of 113 °C. Incorporating nanoscilica particles resulted in an enhancement of the Young's modulus and tensile strength of the epoxy, accompanied by a reduction in the glass transition temperature. The fracture toughness of the unmodified epoxy increased from 1.14 MPa.m1/2 to 1.78 MPa.m1/2 when it was modified with 10 wt.% nanoscilica particles. The fracture surfaces were analysed using a scanning electron microscope (SEM) to determine the toughening mechanisms of the nanoscilica-modified epoxies. The major toughening mechanisms found are particle debonding and void deformation. The atomic force microscope (AFM) is utilised for quantifying the adhesion between nanoparticles and matrix. The innovative chemical recycling process that induces the conversion of thermosets into thermoplastics, which was used in this study to recycle epoxy composites. The epoxy samples that have been cured are immersed in a solution of mild acetic acid at a temperature of 85 °C. The duration needed for complete dissolution is contingent upon the weight and size of the sample. Subsequently, the separated thermoset was retrieved from an acidic solution by causing it to precipitate using a basic coagulant such an aqueous caustic soda solution. An investigation was conducted to examine the influence of the concentration of nanosilica particles and the form of the sample on the time required for recycling. The dissolution time was positively correlated with the increase in particle concentration. The recycling efficiency was also assessed after the reclaimed thermoplastic underwent a washing and vacuum drying process for 24 hours at a temperature of 50 °C. The Tg of the thermoplastic material was determined and found to be within the range of 80 °C.