膨胀阻燃硬质聚氨酯泡沫塑料热降解及燃烧产烟研究

THERMAL DEGRADATION AND SMOKE PRODUCTION DURING COMBUSTION FOR INTUMESCENT FLAME RETARDANT RIGID POLYURETHANE FOAMS

采用热失重、X-射线光电子能谱分析、氧指数及烟密度测试等方法研究了可膨胀石墨(EG)与聚磷酸铵(APP)复配膨胀阻燃硬质聚氨酯泡沫塑料(RPUF)的热降解、燃烧性能及产烟行为.在此基础上利用锥形量热仪考察了EG/APP对磷酸三(β-氯异丙基)酯(TCPP)阻燃RPUF体系燃烧性能的影响.研究表明,EG与APP间的相互作用导致了EG/APP体系高温阶段失重速率下降、残炭量显著上升;EG/APP与RPUF之间的成炭作用以APP的化学成炭为主.与RPUF比较,RPUF/EG/APP的氧指数由19.8%提高至35.4%的同时,烟密度没有显著上升.对比EG、APP及EG/APP阻燃RPUF,体系残炭量越高、炭层耐热氧化能力越强,氧指数就越大;残炭表面越致密,产烟量就越少.添加EG/APP可显著降低含卤体系RPUF/TCPP的热释放、烟释放及CO释放速率,体现了EG与APP复合体系物理与化学膨胀结合的优势.

The thermal degradation behavior and combustion of rigid polyurethane foams （RPUF） with expandable graphite （EG） and ammonium polyphosphate （APP） were investigated by thermal gravimetric analysis （TG）, X-ray photoelectron spectroscopy （XPS） ,limiting oxygen index （LOI） and smoke density test. On this basis,the effect of EG/APP on the combustion of RPUF/tris（fl-chloroisopropyl）phosphate （TCPP） composites was studied by CONE calorimeter. The results showed that the interaction between EG and APP led to lower weight loss rate of EG/APP at high temperatures and a significant increase of char residue at 800 ℃. The char formation between EG/APP and RPUF could be mainly contributed by APP. Compared with RPUF, the LOI of RPUF/EG/APP increased from 19.8% to 35.4% and the smoke density changed little. Compared with the RPUF/EG, RPUF/APP and RPUF/EG/APP, the more the amount and the higher thermal oxidation resistance of char residue,the higher the LOI is ;the more compact of the residue surface,the lower the smoke released is. It was found that the heat release, smoke production rate and CO release rate of RPUF/TCPP were decreased significantly by the addition of EG/APP. The results embodied the advantages of a combination of chemical and physical intumescent flame retardants in the EG/APP system.