Sustainable Reprocessing of Thermoset Composite Waste into Thermoplastics: A Polymer Blend Approach for Circular Material Design
Year: 2025
Type: article
Abstract: Thermoset composites provide excellent strength but pose major recycling challenges due to their crosslinked structure. In this study, epoxy–polyurethane–glass fiber (EPG) wastes were mechanically recycled into low-density polyethylene (LDPE), high-density polyethylene (HDPE), and polyamide-6 (PA6) matrices to produce second-generation thermoplastic composites (STCs). Fillers at 10–50 wt% were processed by single-screw extrusion and compression molding, and the resulting composites were comprehensively characterized. For LDPE, the tensile modulus increased by ~286–589% and tensile strength increased by 40–47% at 20–30 wt% loading, though ductility decreased at higher levels. HDPE composites showed a ~347% rise in modulus and ~24% increase in strength, but performance declined with more than 40 wt% filler. PA6 offered the most balanced outcome, retaining ~70% of its neat tensile strength while achieving an ~300% modulus improvement at 40 wt% loading. Thermal stability was strongly enhanced, with char residue at 700 °C rising from 0.4% to 38.7% in PA6 and from ~2.5% to 33–46% in polyolefins. In contrast, crystallinity decreased (e.g., LDPE 62.2% → 23.7%), and impact strength dropped at a loading above 30 wt%. Overall, the results demonstrate that EPG wastes can be reprocessed into functional composites without compatibilizers, with PA6 providing the most robust property retention at high filler contents.
Source: Journal of Composites Science
DOI: 10.3390/jcs9100565
Institution: University of Alabama at Birmingham
Language: English
Subfield: Polymers and Plastics
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,172
OpenAlex ID: W4415230907