Abstract: A compound flame retardant made of solid tribromoneopentyl alcohol and liquid DMMP was studied when used in grouting polyurethane. A synergetic effect was found between tribromoneopentyl alcohol and DMMP. As the laoding of compound flame retardant (tribromoneopentyl alcohol/DMMP=1:2) increased, the mechanical property of grouting polyurethane increased first and then decreased. When the loading was 24 %, the material gave rise to the highest impact toughness, compressive strength, and tensile strength, i.e., 12.47 kJ/m2, 18.55 Mpa, and 8.11MPa, respectively. In addition the vertical burning time was 8.2 s. The addition of flame retardant did not change the skeleton structure of polyurethane materials.

Key words: polyurethane, grouting materials, flame retardant, mechanical property