阻燃硬质聚氨酯泡沫燃烧热值对阻燃性能的影响

将聚磷酸铵(APP)、磷酸三(β-氯异丙基)酯(TCPP)、氰尿酸三聚氰胺(MCA)、可膨胀石墨(EG)及EG与APP复合阻燃剂分别添加于硬质聚氨酯泡沫(RPUF),采用氧弹量热仪、氧指数仪、燃烧背温测试仪及锥形量热仪研究了阻燃RPUF燃烧热值(HoC)与氧指数、炭层阻隔作用及热释放等阻燃性能参数的相关性;采用X射线光电子能谱表征了RPUF/APP及RPUF/EG/APP体系燃烧热值测试后残炭表面P元素的化学状态. 研究表明,各阻燃RPUF的HoC由低到高的顺序为RPUF/APP,RPUF/EG/APP,RPUF/TCPP,RPUF/MCA,RPUF/EG,其中RPUF/EG/APP的氧指数相对最高,炭层阻隔效应较好,热释放及质量损失相对最低,产烟量适中,综合阻燃性能最好. RPUF/EG/APP燃烧热值测试残炭表面五氧化二磷比例(57.9%)大于RPUF/APP(35.9%). 阻燃RPUF的HoC主要与体系元素组成及阻燃剂HoC的贡献有关,也与膨胀阻燃体系中组分的相互作用有关;而氧指数、炭层的阻隔作用、热及烟释放等阻燃性能主要取决于阻燃机理. 

Effect of Heat of Combustion on Flame Retardancy of Rigid Polyurethan Foams

Mmonium polyphosphate (APP), tris (clorisopropyl) phosphate (TCPP), melamine cyanurate (MCA), expandable graphite (EG) and the mixture of APP and EG were added to rigid polyurethane foams (RPUF) respectively. The relationships between limiting oxygen index (LOI), fire resistance time,heat release rate (HRR) and heat of combustion (HoC) for the flame retardant RPUF were studied by oxygen bomb calorimeter, oxygen index test, fire resistance time test and cone calorimeter. Chemical states of phosphorus atom on the surface of the residues after HoC test were characterized by X-ray photoelectron spectroscopy (XPS). The results show that the sequence for HoC is as follow: RPUF/APP, RPUF/EG/APP, RPUF/TCPP, RPUF/MCA, RPUF/EG, RPUF/EG/APP system has the highest LOI, better char residue blocking effect, lower HRR and mass loss, modest smoke production. The percentage of phosphorus pentoxide in RPUF/APP (57.9%) is higher than RPUF/EG/APP system(35.9%). HoC of flame retardant RPUF not only mainly relates to the composition of system and the contribution of flame retardants but also relates to the interaction between the components; the values of LOI, char residue blocking effect, HRR and smoke production mainly depend on the flame retardant mechanism.