The Influence of Recycled ABS Weight Fraction and OneMonth Natural Weathering on the Mechanical, Physical, and Thermal Properties of Acrylonitrile Butadiene Styrene (ABS)

Acrylonitrile butadiene styrene (ABS) is widely used in various industries, generating significant post-industrial waste. Mechanical recycling and outdoor exposure are both known to degrade ABS; however, their combined effects under natural conditions remain insufficiently understood. This study investigates the influence of reprocessed ABS (rABS) content ( 0 − 100% ) and short-term natural weathering (one month) on the physical and mechanical behaviour of injection-moulded ABS. A total of 160 specimens, representing five material compositions and two exposure conditions (control and weathered), were characterised through density measurement, tensile, flexural, and impact testing, complemented by macro photography. The density remained relatively stable ( 1.05 − 1.06 g/cm^3 ) across all conditions, with a slight increase observed at higher rABS contents. Under control conditions, tensile strength ranged from 41.2 to 44.9 MPa and flexural strength from 66.3 to 73.4 MPa , values approximately 8 − 12% lower than the manufacturer’s nominal datasheet values, indicating acceptable agreement with commercial-grade ABS. Following short-term natural weathering, tensile strength decreased by up to 23.6%, while strain at break was reduced by approximately 86 − 89%, confirming severe embrittlement. Flexural strength exhibited the most pronounced degradation, with reductions of approximately 88.9 − 92.3%, highlighting the high sensitivity of bending resistance to early-stage environmental exposure. In contrast, impact strength showed comparatively moderate variations (within −17.3% to +1.7% ), suggesting that dynamic fracture resistance is less sensitive than quasi-static bending during short-term outdoor exposure. These findings demonstrate that recycled ABS blends, particularly at higher recycled fractions, are more susceptible to embrittlement under natural weathering conditions.