Recycling Poly(Butylene Succinate)/Brewer's Spent Grain Pot Prototypes

The recyclability of pots made entirely from brewer's grains (BSGs) and poly(butylene succinate) (PBS) at a PBS/BSG weight ratio of 70:30, hereafter referred to as MIXr, was evaluated. The resulting pots exhibited tensile strength at break comparable to that of conventional fossil-based polymeric materials. The study aimed to determine the maximum content of recycled materials that could be incorporated into virgin (PBSv) while maintaining acceptable properties, thereby extending the material's life cycle through mechanical recycling before disposal via biodegradation or composting. For comparison, blends of virgin PBS with recycled PBS (PBSv-PBSr) and recycled BSG/PBS material (PBSv-MIXr) were prepared at the same recycled-material contents. The materials were characterized in terms of processability, tensile properties, thermal stability (TGA), chemical group analysis (FTIR), and surface properties. The results showed that the presence of BSG significantly influences the recyclability of the biocomposite. While virgin PBS could incorporate up to 10 wt.% recycled PBS without a significant loss in ductility or thermal stability, PBSv-MIXr blends exhibit a ~20-30% reduction in deformability at MIXr contents ranging from 2 wt.% to 20 wt.% and a reduction in thermal stability ranging from 16-22% at levels of incorporation ranging between 10 wt.% and 40 wt.%.