New Green Bio-Based Binder to Reduce the Poisonous and Harmful Gases Generated from the Combustion of Pyrotechnics

The combustion of pyrotechnics is typically fast and incomplete, resulting in air pollutants such as particulate matters (PM) and poisonous, harmful gases. Demands for environment-friendly pyrotechnics that can be applied at a low temperature with a controllable combustion rate are ever-growing. The study used bio-based dibutyl itaconate (DBI) as the reactive monomer for self-polymerization to prepare poly-dibutyl itaconate (PDIB) with a molecular weight of 5307 g/mol. The molecular structure and thermal stability of PDIB were measured and analyzed. Serving as binders, PDIB and phenolic resin (PF) were, respectively, mixed with CH₃N₅(5-AT) and KNO₃to prepare a pyrotechnic formulation. The final products were tested and compared in terms of their safety, mechanical, combustion, and environment-friendly performances. The results showed that the PDIB binder pyrotechnics is featured with a slower complete combustion, a large amount of gases produced, a small amount of combustion residues, a low PM2.5 concentration, and environmentally friendly flue gases. These prove that PDIB can be used as a new environmentally friendly binder for pyrotechnics. In addition, this study discovered the "string bag" theory of the pyrotechnic binder, which implies that the monomer structure of the binder and the ignition point of the polymer are the key to determine the combustion rate of pyrotechnics.