Department of Chemistry and Technology of Polymers, Cracow University of Technology, Warszawska 24, 31-155 Cracow, Poland.
Latvian State Institute of Wood Chemistry, Dzerbenes 27, LV-1006 Riga, Latvia.
Int J Mol Sci. 2022 Oct 16;23(20):12386. doi: 10.3390/ijms232012386.
In this article, rigid polyurethane foams obtained with the addition of a bio-polyol from rapeseed oil, were modified with the dimethyl propane phosphonate as additive flame retardant and two reactive flame retardants diethyl (hydroxymethyl)phosphonate and diethyl bis-(2-hydroxyethyl)-aminomethylphosphonate. The influence of used flame retardants on the foaming process and characteristic processing times of tested polyurethane systems were determined. The obtained foams were tested in terms of cell structure, physical and mechanical properties, as well as flammability. Modified foams had worse mechanical and thermal insulation properties, caused by lower cellular density and higher anisotropy coefficient in the cross-section parallel to the foam rise direction, compared to unmodified foam. However, the thermal conductivity of all tested foam materials was lower than 25.82 mW/m∙K. The applied modifiers effectively reduced the flammability of rigid polyurethane foams, among others, increasing the oxygen index above 21.4 vol.%, reducing the total heat released by about 41-51% and the rate of heat release by about 2-52%. A correlation between the limiting oxygen index values and both total heat released parameters from the pyrolysis combustion flow calorimetry and cone calorimetry was observed. The correlation was also visible between the value of the heat release capacity (HRC) parameter obtained from the pyrolysis combustion flow calorimetry and the maximum average rate of heat emission (MARHE) from the cone calorimeter test.
在本文中，通过添加菜籽油生物多元醇，制备了刚性聚氨酯泡沫，并用二甲基丙烷膦酸酯作为添加剂阻燃剂，以及两种反应性阻燃剂二羟甲基磷酸二乙酯和二乙基双（2-羟乙基）氨基甲基膦酸酯对其进行改性。确定了所使用的阻燃剂对发泡过程和测试的聚氨酯体系的特征加工时间的影响。对获得的泡沫进行了细胞结构、物理和机械性能以及可燃性方面的测试。与未改性的泡沫相比，改性泡沫的机械和热绝缘性能较差，这是由于细胞密度较低和与泡沫上升方向平行的横截面各向异性系数较高所致。然而，所有测试的泡沫材料的导热系数均低于 25.82 mW/m·K。所应用的改性剂有效地降低了刚性聚氨酯泡沫的可燃性，例如，将氧指数提高到 21.4 体积%以上，将总放热量降低约 41-51%，将放热量降低约 2-52%。观察到极限氧指数值与热解燃烧流动量热计和锥形量热计中的总放热量参数之间存在相关性。还可以观察到从热解燃烧流动量热计获得的热释放量（HRC）参数与锥形量热计测试中的最大平均热发射率（MARHE）之间的相关性。
