Mechanical fragmentation of polyester textiles for controlled particle generation

Mechanical fragmentation can create engineered secondary feedstocks from waste polyester textiles, but its process-property trade-offs remain unclear. This study varied pass number, sieve cassette configuration, and rotation speed using a 100% polyethylene terephthalate (PET) interlock fabric as a model substrate. Particles were characterized by image analysis, sieving, Rosin-Rammler modeling, and SEM. Independent milling trials quantified process performance, and FTIR spectroscopy and alkaline hydrolysis evaluated chemical changes and mass-loss response. At 3000 rpm, increasing passes from C1 to C5 reduced the image-based median equivalent diameter by 35.2% with the 1.5 mm trapezoidal-perforated cassette (B1.5) and by 38.2% with the 10 mm square-perforated cassette (B10). B1.5 sieving median decreased by 59.0%, whereas rotation speeds of 1000-3000 rpm produced no consistent monotonic effect. Five-pass B1.5 and B10 trials yielded material recoveries of 84.75 ± 1.67% and 89.89 ± 1.10%, cumulative dust fractions of 7.57 ± 0.88% and 5.89 ± 0.67%, and laboratory cycle times of 82.09 ± 0.59 and 53.49 ± 0.70 min, respectively. Cutting-mill-only nominal specific electricity demands, estimated from the 5 kW nameplate power, were 11.74 ± 0.09 and 11.58 ± 0.22 kWh/kg. FTIR detected no major changes in characteristic PET bands. Under identical hydrolysis conditions, three-hour mass loss increased from 51.67 ± 2.52% for the original fabric to 78.00 ± 2.00% for A3000 × B1.5 × C5. Results establish laboratory-scale empirical relationships between cutting-mill settings and PET fragment characteristics while revealing trade-offs among size reduction, recovery, process demand, and alkaline-hydrolysis response.