Insights into characteristics and thermokinetic behavior of potential energy-rich polysaccharide based on chitosan

To explore polysaccharides for developing energetic biopolymers, a promising energy-rich nitrochitosan (NCS) was successfully prepared through electrophilic nitration of chitosan. The chemical structure and morphology of the synthesized NCS and its precursor were confirmed by infrared spectroscopy, elemental analysis, and scanning electron microscopy. The energetic performance, thermal behavior, and degradation kinetics of NCS were also evaluated. The results showed that the designed nitrogen-rich (\(Nc\hspace{0.17em}\)= 16.79%) NCS presents excellent energetic features, such as a calorific value of 10,573 J/g, a density of 1.708 g/cm³, an impact sensitivity of 15 J, and a detonation velocity of 7788 m/s, which are markedly better than those of NC and GAP. Meanwhile, the thermal investigation based on deconvoluted non-isothermal DSC experiments combined with isoconversional kinetic methods indicated that NCS displays two consecutive exothermic decomposition events within the temperature range of 133–180 °C and 185–240 °C, and exhibits apparent activation energies of 74 kJ/mol and 152 kJ/mol, respectively, which are lower than the common thermolysis energy range of NC (140–190 kJ/mol), demonstrating the improved reactivity of the aforementioned energetic NCS. Overall, this study established that NCS could serve as an outstanding energetic polysaccharide for potential application in high-performance composite explosives and solid rocket propellants.