Effect of Flame Retardants on Properties of Microporous Polyurethane Elastomers

Microporous polyurethane elastomers (MPUEs) with flame retardant function were prepared by using expandable graphite (EG), expandable graphite/melamine polyphosphate (EG/MPP) and expandable graphite/melamine polyphosphate/dimethyl methylphosphonate (EG/MPP/DMMP) as flame retardants. The effect of flame retardants on thermal degradation behavior and flame retardancy of MPUEs were studied by thermogravimetric analysis, limiting oxygen index (LOI), horizontal and vertical combustion test. The effects of flame retardants on mechanical properties, dynamic vibration reduction and creep resistance were analyzed. The results show that the addition of EG alone has obvious flame retardant effect on MPUE when the addition amount is more than 20%, but the dynamic damping effect and creep resistance of MPUE become worse with the increase of EG content. When EG was combined with MPP, the flame retardancy of MPUE is significantly improved, but the dynamic vibration reduction and creep resistance of MPUE are still high. When EG/MPP/DMMP was combined, the flame retardant performance is further improved, and the dynamic vibration damping performance and creep resistance are improved. When the addition amount is 11%, the LOI of MPUE is still 27.8%, and the dynamic and static stiffness ratio is reduced to less than 1.35. © 2024 Sichuan University. All rights reserved.