典型有机建筑保温材料热解动力学行为特性研究
发布时间：2018-10-21 18:26
【摘要】：近些年来,在国家大力倡导建筑节能的社会背景下,保温材料特别是有机建筑保温材料由于其卓越的保温隔热性能以及成本低廉、耐压防水等特性被广泛应用于建筑保温结构中。然而由于有机类建筑保温材料遇火易燃且燃烧易释放有毒烟气,往往会引发火灾并造成巨大的人员伤亡和财产损失。因此,为了更好的预防火灾事故的发生,降低发生火灾事故的危险性和严重性,深入研究这些易燃建筑保温材料的火灾特点显得尤为必要。论文采用热重-差示扫描量热(TG-DSC)联用技术,对模塑聚苯乙烯泡沫(EPS)、聚氨酯硬泡(PU)、酚醛泡沫(PF)三种典型有机建筑保温材料在不同参数下的热解动力学行为进行研究,深入对比分析了气氛、升温速率等参数对三种材料的热解动力学参数及反应机理函数的影响。研究发现:(1)聚苯乙烯泡沫材料在空气和氮气气氛下的热解曲线形状相似,都表现为两个阶段,第二阶段为主要失重阶段且都几乎没有热解残渣。氮气气氛的热解反应起止温度和峰温高于空气,说明有氧存在热解反应更易进行。等转化率法计算空气气氛下热解反应为144.55kJ/mol,活化能随转化率增加而有所增加。氮气气氛下为193.34k J/mol,活化能在热解初期略增加,随后变化很小。与空气气氛相比,氮气气氛下活化能值变化非常小,较为稳定。利用C-R法求得得到了聚苯乙烯泡沫在空气气氛下热解机理函数属于成核和核生长A2/3描述,氮气气氛下的反应机理函数属于反应级数F3描述。(2)聚氨酯硬泡在空气和氮气氛围下的热解曲线形状明显不同,分别分为三个阶段和两个阶段,两种氛围下的第一阶段反应温度区间接近,这个阶段的反应过程相似,剩余残渣量在4%和23%,空气气氛热解反应更为彻底。空气气氛下,聚氨酯泡沫活化能呈现出逐渐增大的趋势,α在0.1~0.5,活化能值为79.11kJ/mol,0.7~0.9之间,活化能为124.58kJ/mol。氮气气氛下为139.33kJ/mol,活化能值随转化率的增加逐渐增加。两种气氛下热解初始活化能都很小,说明聚氨酯硬泡受热易发生热损。C-R法求得聚氨酯硬泡在空气氛围的热解机理属于一维扩散D1描述,氮气氛围为枝状成核P-T方程B4描述。(3)酚醛泡沫在空气氛围下的热解曲线随升温速率的升高向高温区迁移,热解过程有两个阶段,剩余残渣约21%且主要热失重在第二阶段。酚醛泡沫受热就发生较小热损且初始阶段的持续时间长。等转化率法求得为45.26kJ/mol,转化率从0.1至0.2的温度跨度大,主反应阶段晚且残渣量大,说明了酚醛不燃、难燃的特点。C-R法求得酚醛泡沫在空气氛围的机理函数为反应级数F3/2描述。(4)三种有机保温材料对应火灾危险性程度大小依次为聚氨酯硬泡最大、模塑聚苯乙烯次之、酚醛最小。
[Abstract]:In recent years, in the context of the country's strong advocacy of building energy conservation, thermal insulation materials, especially organic building insulation materials, due to its excellent thermal insulation performance and low cost, The characteristics of pressure-proof and water-proof are widely used in building insulation structure. However, due to the flammability of organic building heat preservation materials and the release of toxic smoke easily, it will often lead to fire and cause huge casualties and property losses. Therefore, in order to better prevent the occurrence of fire accidents and reduce the danger and severity of fire accidents, it is particularly necessary to study the fire characteristics of these flammable building insulation materials. In this paper, thermogravimetric differential scanning calorimetry (TG-DSC) was used to study the pyrolysis kinetics of three typical organic building insulating materials, (EPS), polyurethane rigid foam, (PU), phenolic foam (PF), molded polystyrene foam under different parameters. The effects of atmosphere, heating rate and other parameters on the pyrolysis kinetic parameters and reaction mechanism functions of three kinds of materials were compared and analyzed. The results show that: (1) the pyrolysis curves of polystyrene foam materials in air and nitrogen atmosphere are similar, and the second stage is the main weightlessness stage and there is almost no pyrolysis residue in the second stage. The pyrolysis temperature and peak temperature in nitrogen atmosphere were higher than those in air, which indicated that the pyrolysis reaction was easier in aerobic atmosphere. The iso-conversion method was used to calculate the pyrolysis reaction at 144.55kJ / mol in air atmosphere, and the activation energy increased with the increase of conversion. In nitrogen atmosphere, the activation energy increases slightly at the initial stage of pyrolysis, and then changes slightly in the range of 193.34k / mol. Compared with air atmosphere, the change of activation energy in nitrogen atmosphere is very small and stable. By means of C-R method, the pyrolysis mechanism function of polystyrene foam in air atmosphere is obtained, which belongs to the description of nucleation and nuclear growth A _ 2 / 3. The reaction mechanism function in nitrogen atmosphere belongs to the description of reaction order F3. (2) the pyrolysis curve of polyurethane rigid foam in air and nitrogen atmosphere is obviously different, which is divided into three stages and two stages, respectively. The reaction temperature range of the first stage is close to that in the two kinds of atmosphere. The reaction process in this stage is similar, the residual residue is 4% and 23%, and the pyrolysis in air atmosphere is more thorough. In the air atmosphere, the activation energy of polyurethane foam showed an increasing trend, 伪 was 0.1 鈩，
本文编号：2285970
[Abstract]:In recent years, in the context of the country's strong advocacy of building energy conservation, thermal insulation materials, especially organic building insulation materials, due to its excellent thermal insulation performance and low cost, The characteristics of pressure-proof and water-proof are widely used in building insulation structure. However, due to the flammability of organic building heat preservation materials and the release of toxic smoke easily, it will often lead to fire and cause huge casualties and property losses. Therefore, in order to better prevent the occurrence of fire accidents and reduce the danger and severity of fire accidents, it is particularly necessary to study the fire characteristics of these flammable building insulation materials. In this paper, thermogravimetric differential scanning calorimetry (TG-DSC) was used to study the pyrolysis kinetics of three typical organic building insulating materials, (EPS), polyurethane rigid foam, (PU), phenolic foam (PF), molded polystyrene foam under different parameters. The effects of atmosphere, heating rate and other parameters on the pyrolysis kinetic parameters and reaction mechanism functions of three kinds of materials were compared and analyzed. The results show that: (1) the pyrolysis curves of polystyrene foam materials in air and nitrogen atmosphere are similar, and the second stage is the main weightlessness stage and there is almost no pyrolysis residue in the second stage. The pyrolysis temperature and peak temperature in nitrogen atmosphere were higher than those in air, which indicated that the pyrolysis reaction was easier in aerobic atmosphere. The iso-conversion method was used to calculate the pyrolysis reaction at 144.55kJ / mol in air atmosphere, and the activation energy increased with the increase of conversion. In nitrogen atmosphere, the activation energy increases slightly at the initial stage of pyrolysis, and then changes slightly in the range of 193.34k / mol. Compared with air atmosphere, the change of activation energy in nitrogen atmosphere is very small and stable. By means of C-R method, the pyrolysis mechanism function of polystyrene foam in air atmosphere is obtained, which belongs to the description of nucleation and nuclear growth A _ 2 / 3. The reaction mechanism function in nitrogen atmosphere belongs to the description of reaction order F3. (2) the pyrolysis curve of polyurethane rigid foam in air and nitrogen atmosphere is obviously different, which is divided into three stages and two stages, respectively. The reaction temperature range of the first stage is close to that in the two kinds of atmosphere. The reaction process in this stage is similar, the residual residue is 4% and 23%, and the pyrolysis in air atmosphere is more thorough. In the air atmosphere, the activation energy of polyurethane foam showed an increasing trend, 伪 was 0.1 鈩，
本文编号：2285970
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