三聚氰胺植酸/硬质聚氨酯泡沫复合材料的制备及其热解动力学特性

Preparation and pyrolysis kinetics of melamine phytates/rigid polyurethane foam composites

以实验室自制的三聚氰胺植酸(MEL-PA)为阻燃剂,采用一步法全水发泡工艺制备一系列三聚氰胺植酸/硬质聚氨酯泡沫(MEL-PA/RPUF)复合材料。采用热重分析(TG)与热分析动力学研究复合材料热稳定性,揭示其降解机制。研究表明,随着MEL-PA负载量的增加,MEL-PA/RPUF在700℃的残炭率逐渐提升。结合TGA数据,通过Coats-Redfern和Horowitz-Metzger积分法计算复合材料主要降解阶段的反应等级n、活化能E及指前因子A。结果表明,空气氛围中MEL-PA促进了复合材料的初始降解,而在高温阶段使复合材料具有更高的热稳定性,并且两种计算方法具有相同规律。N_(2)氛围中,MEL-PA30/RPUF(MEL-PA质量分数为10.3wt%)与RPUF相比,n增大,E升高。表明MEL-PA30/RPUF的反应更为复杂,热稳定性更高。通过Criado法进行数学模型与实验分析,验证了Coats-Redfern法的可行性。MEL-PA/RPUF复合材料的热氧化降解动力学研究结果为分析不同阻燃体系的RPUF的阻燃性能提供参考依据。

A series of melamine phytates/rigid polyurethane foam(MEL-PA/RPUF) composites were prepared by one-step water-blown method with MEL-PA as flame retardant. Thermogravimetric analysis(TG) and thermal analysis kinetics were used to study the thermal stability of the composites and reveal its degradation mechanism. The results show that the char residues of MEL-PA/RPUF gradually increases at 700℃ with the increase of MEL-PA loading. Based on TGA data,the reaction grade n,activation energy E and pre exponential factor A of the main degradation stage for the composites were calculated by the Coats-Redfern and Horowitz-Metzger integration methods. The results show that MEL-PA promotes the initial degradation of the composites in air atmosphere,while the MELPA/RPUF composites have higher thermal stability in the high temperature stage,and the two calculation methods have the same law. In N_(2) atmosphere,MEL-PA30/RPUF(mass fraction of MEL-PA is 10.3 wt%) has higher n and E compared with RPUF. The results indicate that the reaction of MEL-PA30/RPUF is more complex and the thermal stability is higher. The mathematical model and experimental analysis by Criado method verify the feasibility of the Coats-Redfern method. The results of thermal degradation kinetics of MEL-PA/RPUF composites provide reference for the analysis of flame retardation performance of RPUF with different flame retardation systems.