DNA as a flame retardant additive for low-density polyethylene

Deoxyribonucleic acid (DNA) was investigated as a flame retardant (FR) additive for melt-compounded formulations with low-density polyethylene (LDPE) and compared to LDPE compounded with melamine polyphosphate (MPP), one of the industry standard intumescent FR additives for plastics. DNA showed a much greater compatibility with the LDPE matrix than MPP. At high loading levels, DNA showed minimal increases in compounding torque, while MPP increased torque by over 20%. Qualitative evaluation using SEM and EDS showed that DNA/LDPE blends had significantly improved cross-sectional morphology, with fewer microaggregates and improved particle dispersion than MPP/LDPE. Horizontal burn testing showed that DNA markedly reduced flame burn distances in LDPE above loading levels of 5% w/w. Biochemical characterization of heat-treated DNA revealed that DNA undergoes denaturation, fragmentation, and oxidation during compounding, but these processes did not appear to have an effect on its FR properties. This study expands the field of DNA-based FR beyond specialty substrates, and establishes DNA as a viable green FR additive for commodity polymer applications. [Display omitted] •DNA was investigated as a flame retardant additive with low-density polyethylene (LDPE).•Flame retardant properties of DNA were compared to melamine polyphosphate (MPP).•DNA showed significantly improved bulk compatibility with LDPE.•DNA/LDPE blends had markedly reduced flame spread in horizontal flame tests.•Biochemical characterization of DNA was performed before and after heat treatment.