Better Material Properties and Faster Catalyzed Chemical Recycling for Poly(L-Lactide) Using a Simple Commercial...

Poly(L-lactide) (PLLA) is the largest volume commercial bio-derived plastic, but its brittleness and end-of-life recycling remain challenges. Here, glycerol ethoxylate (GEO), a branched ethylene glycol derivative, both toughens commercial PLLA and accelerates its catalyzed chemical recycling to L-lactide. A series of GEO-PLLA blends, containing 2-20 wt.% GEO, show significantly improved ductility and toughening compared to pure PLLA. The lead 10 wt.% GEO-PLLA sample achieves 9x higher elongation at break (191% ± 4%) and 6x higher tensile toughness (57.9 ± 1.9 MJ m^-3), while retaining desirable tensile strength (36.3 ± 1.5 MPa), thermal properties (T_g = 39°C and T_m = 149°C) and crystallinity (25%). The GEO-PLLA samples are efficiently chemically recycled to L-lactide, showing both high recycling activity (TOF = 2240 ± 73 h^-1) and quantitative selectivity for L-lactide (> 99%). The recycling is performed neat, at 180°C, using low loadings of commercial Sn(II)Oct₂ catalyst. The 10 wt.% GEO-PLLA sample shows significantly faster chemical recycling than PLLA, with k_obs = 22.9 ± 0.8 h^-1 versus k_obs = 1.8 ± 0.2 h^-1 for PLLA. This recycling process is successful even with contamination from other commercial plastics, demonstrating its applicability to future postconsumer waste streams.