阻燃硬质聚氨酯泡沫制备及空气中热解特性

Preparation and Thermal Decomposition Characteristics in Air of Fire-retarded Rigid Polyurethane Foam

以可膨胀石墨(EG)和次磷酸铝(AHP)为阻燃剂,采用一步合成法制备了硬质聚氨酯泡沫/可膨胀石墨复合材料和硬质聚氨酯泡沫/次磷酸铝复合材料。采用热重分析(TG)法对阻燃型以及非阻燃型聚氨酯泡沫在10、20、30、40、50℃/min5种不同升温速率下的热解过程及反应动力学进行了研究。实验结果表明,空气氛围下3种聚氨酯样品均存在2个主要失重阶段,样品初始分解溫度由低到高为:RPUF/EG<RPUF<RPUF/AHP,其温度分别为187.6、198.83、203.24℃。随着升温速率的增加,热解向高温区移动,主反应区逐渐增大,且最大热失重速率逐渐增大。加入可膨张石墨与次嶙酸铭均能提高样品成炭量。与此同时,运用Kissinger-Akahira-Sunose(KAS)和Ozawa-Flynn-Wall(OFW)方法求得,不同转化率时,3种聚氨酯样品活化能由大到小为:RPUF/AHP<RPUF<RPUF/EG,采用KAS方法求得的活化能分别为129.36、151.23、169.45kJ/mol;采用0FW方法求得的活化能分别为123.61、146.92、166.12kJ/mol。

Expanded graphite (EG) and aluminum hypophosphite (AHP) were used as flame retardant to prepare rigid polyurethane foam/expanded graphite composites and rigid polyurethane foam/aluminum hypophosphite composites by one-step water-blown method.Thermal decomposition and kinetics of fire-retarded and non fire-retarded polyurethane foams were studied by TGA (thermogravimetric analysis) at five various heating rates of 10,20,30,40,50 ℃/min in air environment.The thermal analysis research indicated that there were two main weight loss processes during the thermal decomposition of polyurethane,the initial decomposition temperature of samples was RPUF/EG < RPUF < RPUF/AHP successively from low to high with 187.6,198.83,203.24℃.With the increasing heating rates,the initial temperature increased,the main reaction area increased gradually,and the maximum thermal decomposition rate increased gradually.It was revealed that EG and AHP enhanced char residue of the composites.By Kissinger-Akahira-Sunose (KAS) and Ozawa-Flynn-Wall (OFW) methods,the activation energy of polyurethane followed as: RPUF/AHP < RPUF < RPUF/EG,with 129.36,151.23,169.45 kJ/m ol for KAS method;123.61,146.92,166.12 kJ/m ol for OFW method,respectively.