Thermoplastic Polyurethane-Encapsulated Melamine Phosphate Flame Retardant Polyoxymethylene

Due to its “unzipping” degradation mode and poor compatibility with most other flame retardants, polyoxymethylene (POM) is the most difficult flame-retarded polymer among macromolecular materials. In this project, we took advantage of thermoplastic polyurethane (TPU) resin, which possesses good compatibility with POM, serving as an encapsulation layer, and the carrier resin of the nitrogen-phosphorus composite flame retardant melamine phosphate to achieve even and fine dispersion of the flame retardant particles in the POM matrix. The improved morphology of the dispersion phase can markedly modify the flame retardancy and good mechanical performance. Additionally, the encapsulation of TPU avoids direct contact of the flame retardant with POM, thus also advantageous to the enhancement of its material performance. Moreover, as an efficient formaldehyde absorbent and toughening agent, TPU itself can greatly improve the flame retardancy, thermal stability, and toughness of the flame retardant POM. Therefore, this method provides a simple and effective method to prepare flame retardant POM with good comprehensive performance.