Aluminum hypophosphite in combination with expandable graphite as a novel flame retardant system for rigid polyurethane foams
Aluminum hypophosphite in combination with expandable graphite as a novel flame retardant system for rigid polyurethane foams
复制标题
次磷酸铝与可膨胀石墨组合作为硬质聚氨酯泡沫的新型阻燃系统
DOI：
10.1002/pat.3348
复制
发表时间：
2014-09-01
影响因子：
3.4
通讯作者：
Yuen, Richard K. K.
中科院分区：
文献类型：
--
作者：
Yang, Hongyu;Wang, Xin;Yuen, Richard K. K.
研究了可膨胀石墨（EG）和次磷酸铝（AHP）对硬质聚氨酯泡沫塑料（RPUFs）阻燃性能的协同效应。采用一步法和自由发法制备了一系列含有EG和AHP的阻燃RPUF。通过极限氧指数（LOI）测试、垂直燃烧（UL-94）测试、热重分析和微量燃烧量热仪对RPUF杂化材料的阻燃性能、热降解性能和燃烧性能进行了表征。LOI和UL-94结果表明，具有10wt%EG和5wt%AHP的RPUF样品通过UL-94 V-0等级，并达到相对高的LOI值28.5%，这比RPUF中的其它EG/AHP比率在相等的填料负载下优越上级。微型燃烧量热仪结果表明，EG和AHP的掺入降低了RPUF的峰值放热速率和总放热速率，从而显著降低了RPUF的火灾危险性。热重分析结果表明，EG和AHP的加入提高了RPUF的热稳定性，扫描电镜和拉曼光谱分析表明，加入EG和AHP后，RPUF的炭层在高温下的耐热性也有所提高。热重/红外光谱分析表明，EG和AHP的加入显著降低了烃类和醚类等可燃气体的生成量。最后对协同阻燃机理进行了探讨和推测。版权所有© 2014约翰威利父子有限公司.
The main aim of this work was to investigate the synergistic effect of expandable graphite (EG) and aluminum hypophosphite (AHP) on the flame retardancy of rigid polyurethane foams (RPUFs). A series of flame retardant RPUF containing EG and AHP were prepared by one-shot and free-rise method. The flame retardant, thermal degradation, and combustion properties of RPUF hybrids were characterized through limiting oxygen index (LOI) test, vertical burning (UL-94) test, thermogravimetric analysis and microscale combustion calorimeter. The LOI and UL-94 results showed that the RPUF sample with 10 wt% EG and 5 wt% AHP passed UL-94 V-0 rating and reached a relatively high LOI value of 28.5%, which is superior over other EG/AHP ratios in RPUF at the equivalent filler loading. Microscale combustion calorimeter results revealed that the incorporation of EG and AHP into RPUF reduced the peak heat release rate and total heat release, thus decrease the fire risk of RPUF significantly. Incorporation of EG and AHP improved the thermal stability of RPUF as observed from the thermogravimetric analysis results and also enhanced the thermal resistance of char layer at high temperature from scanning electron microscopy and Raman spectroscopy. Moreover, it could be seen from thermogravimetric analysis/infrared spectrometry spectra that the addition of EG and AHP significantly decreased the combustible gaseous products such as hydrocarbons and ethers. Finally, the synergistic mechanism in flame retardancy was discussed and speculated. Copyright © 2014 John Wiley & Sons, Ltd.