Tudor Andrei Rusu, Rusu Tiberiu
dry, washing-free processing is a technically promising pathway for valorising plastic waste streams currently considered non-recyclable, potentially reducing production cost by 60-70% relative to wet recycling, pending additional characterisation identified as priorities for future work.
PROBLEM STATEMENT: Contaminated mixed plastic waste-bearing metallic, paper, cardboard and organic residues-remains largely excluded from mechanical recycling because conventional routes require a costly, water- and energy-intensive washing-drying pretreatment. Research gap: No published study combines a fully dry, washing-free valorisation route for such waste with certified mechanical characterisation and a quantified CO2 mass balance that explicitly credits elimination of the washing-drying stage.
METHODOLOGY: This study presents DMP (Downcycled Mixed Plastic), a patented (OSIM, Romania) dry valorisation process based on continuous single-screw extrusion (D = 150 mm, L/D = 17.3), characterised through differential scanning calorimetry (DSC), certified mechanical/thermal testing at accredited Romanian laboratories, Weber-number dispersion analysis, and a process-parameter sensitivity study.
KEY FINDINGS: The composite exhibits certified mechanical properties (tensile strength 9.22 MPa, elongation at break 112.8%, compressive strength 14.5 MPa); composition-property analysis across four batches shows that increasing the PP weight fraction from 20 to 28 wt% raises tensile strength by 8.3% while reducing elongation by 5.2%; a computed Weber number (We = 166.7 ≫ We_crit) is consistent with fine PP-phase dispersion within the PE matrix; the sensitivity study confirms statistically robust structure-property relationships (R2 = 0.93-0.98); and the CO2 mass balance establishes a net avoidance of 3.150 t CO2 eq per tonne of waste processed relative to conventional wet recycling.
SIGNIFICANCE: dry, washing-free processing is a technically promising pathway for valorising plastic waste streams currently considered non-recyclable, potentially reducing production cost by 60-70% relative to wet recycling, pending additional characterisation identified as priorities for future work.