Depolymerisation of kraft lignin to obtain high value-added products: antioxidants and UV absorbers

This study demonstrates that bio-based products of lignin depolymerisation can potentially replace common antioxidants and UV absorbers in the plastics and cosmetics industries. The kraft lignin Indulin AT was used to obtain low-MW lignin and monomers & oligomers rich in phenolic hydroxyl groups. Both thermo-oxidative stability and antioxidant activity significantly improved upon lignin depolymerisation. The results from oxidation induction time differential scanning calorimetry (OIT-DSC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) measurements show that the lignin based depolymerisation products are comparable with commercial antioxidants like pentaerythritol-tetrakis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate) (Irganox 1010). UV/vis spectroscopy was investigated to confirm absorption of the depolymerisation products in the UVA and UVB range (280-400 nm).

Automated summary

This study demonstrates the potential of lignin depolymerisation to produce bio-based products that can replace common antioxidants and UV absorbers in the plastics and cosmetics industries. The depolymerisation process significantly improves the thermo-oxidative stability and antioxidant activity of the lignin products. The absorption of UV light by these depolymerisation products is comparable to commercial antioxidants.