Sustainable Thermal Paper Formulation Using Lignocellulosic Biomass Fractions

Abstract:Thermal paper presents widely recognized health hazards due to its formulations containing Bisphenol A (BPA) and Bisphenol S (BPS) as color developers with limited research on safer alternatives. Here, we introduce sustainable thermal paper formulations built with functionalized lignin polymers and lignin-derived esters, combined with a sensitizer derived from xylan. Light-colored lignin polymer was obtained via Sequential Aldehyde Assisted Fractionation (SAAF), which reduced chromophore concentration through multiple extraction cycles. Good performance was achieved with polymeric lignin (color density at 120 °C ≈ 0.8 - 1.1) when combined with xylan-derived diformylxylose (DFX), each of which are produced directly by simple biomass fractionation. Coatings remained stable for over a year under ambient conditions. Finally, lignin-based developers showed estrogenic activity that was 2-3 orders of magnitude lower than BPA and 1-2 orders of magnitude lower than BPS, while the DFX sensitizer showed no signs of estrogenic activity or toxicity to bacteria or algae.