Upcycling polyester fleece fabric waste into sustainable composites using glass microsphere modified epoxy matrix: performance investigation

This research explores sustainable usage of waste fabric, specifically knitted three-thread polyester fleece fabric (3-TPEF), to reinforce epoxy. Different orientations of the fabric (wale and course), varying weight proportions, and fibers derived from the fabric are studied. The impact of unmodified and epoxy-functionalized glass microspheres (UGM and FGM) on the mechanical and thermo-mechanical properties of composites is investigated. Custom-made mold was utilized to regulate fabric weight, reduce air traps, and collect surplus resin released during compression. Compared to neat epoxy, FGM-incorporated fabric-reinforced composites exhibit increased tensile strength (43 vs. 51 MPa), tensile modulus (2.2 vs. 3.5 GPa), flexural strength (83 vs. 98 MPa), flexural modulus (2.9 vs. 4.3 GPa), and impact strength (20 vs. 26 kJ/m²). Weight loss during decomposition decreased from 76.9% (neat epoxy) to 57.7% (composite), indicating improved thermal stability. Dynamic mechanical analysis shows a 1.5-fold increase in relative loss modulus area and tan-δ area, highlighting the improved damping and energy-dissipation capabilities. Moldability and formability involved in the fabrication were demonstrated by manufacturing brake levers and decorative wall panels using 3D-printed mold and wire mesh. The enhanced performance of composites fabricated through this sustainable circular economy approach makes them suitable for automotive and construction applications.