Exploring the effect of kraft lignin on the stability and decomposition kinetics of nitrated cellulose carbamate

This study systematically investigated the stability and thermo-kinetic properties of a high-energy-density nitrated cellulose carbamate (NCC) system stabilized with Kraft lignin. The performance of lignin as a stabilizer was rigorously compared to that of two conventional stabilizers, 2-nitrodiphenylamine (2-NDPA) and 1,3-dimethyl-1,3-diphenylurea (C-II), focusing on their effects on the molecular structure and thermo-kinetic behavior of NCC. Structural characterization techniques, including Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD), demonstrated that lignin effectively interacts with and stabilizes the nitroxyl radicals generated during the thermolysis of the NO2 bond in the NCC matrix. Enhanced thermal stability of the lignin-stabilized NCC, relative to the baseline NCC, was confirmed through thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), highlighting the stabilizing influence of the incorporated organic stabilizers. Additionally, the investigation of the thermolysis kinetics of stabilized NCC demonstrated a moderate increase in the Arrhenius parameters compared to the NCC baseline, indicating enhanced thermal stability, improved storage safety, and broader safety margins. Compared to conventional stabilizers like 2-NDPA and C-II, Kraft lignin offers a safer, bio-based alternative with lower toxicological risks. Its stabilization mechanism involves electrophilic nitration, avoiding nitrosamine formation and minimizing hazardous by-products. This finding highlights the enhanced thermal stability of the stabilized system. Importantly, this study contributes to the ongoing development of environmentally friendly stabilizers for nitrate ester-based energetic materials.