Addition flame-retardant effect of nonreactive phosphonate and expandable graphite in rigid polyurethane foams

作者：Li, Linjie; Chen, Yajun^*; Qian, Lijun^*; Xu, Bo; Xi, Wang

来源：Journal of Applied Polymer Science, 2018, 135(10): 45960.

DOI：10.1002/app.45960

• flame retardance
• foams
• polyurethane

A series of flame-retardant rigid polyurethane foams (RPUFs) containing nonreactive phosphonate (5-ethyl-2-methyl-1,3,2-dioxaphosphorinan-5-yl) methyl dimethyl phosphonate P-oxide (EMD) and expandable graphite (EG) were prepared by water blown. The flame-retardant properties and mechanism of EMD/EG on RPUFs were systematically investigated. The EMD/EG system effectively increased the limiting oxygen index (LOI) value and decreased the values of total heat release (THR), av-effective heat of combustion (EHC), pk-heat release rate (HRR), total smoke release (TSR) of RPUFs. The impact values of LOI, THR, and av-EHC resulted by EMD/EG system are nearly equal to the sum of the impact values by EMD and EG individually in RPUFs, which implies the addition flame-retardant effect from EMD and EG. EMD alone exerted excellent gas-phase flame-retardant effect by releasing PO fragments with quenching effect. The firm residue produced by EMD combined well with the loose and worm-like expanded graphite from EG further to form compact and expanded char layer, which brought excellent barrier effect and filtration effect to matrix. That's why pk-HRR and TSR values of RPUF reduced. Depending on the simultaneous actions of EMD/EG system in gas phase and condensed phase during combustion, the flame-retardant effects from nonreactive phosphonate and EG on RPUFs were added together.

• 出版日期2018-3-10
• 单位北京工商大学