改性水滑石的制备及在硅橡胶泡沫阻燃抑烟中的应用

Preparation of Modified Hydrotalcite and Its Application in Flame Retardant and Smoke Suppression of Silicone Rubber Foam

采用共沉淀法分别制备出水滑石(Zn-Mg-Al-LDHs)与含稀土元素La改性水滑石(Zn-Mg-Al-La-LDHs)阻燃剂样品,通过X射线衍射、能谱仪对阻燃剂样品进行表征。利用热重分析、氧指数和锥形量热等研究了水滑石及含稀土元素La改性水滑石对硅橡胶泡沫材料(SRF)阻燃及抑烟性能的影响。结果表明,Zn-Mg-Al-LDHs和Zn-Mg-Al-La-LDHs被成功制备,将两者添加到SRF中,垂直燃烧等级均达到V-0级别,添加量为20%(质量分数)的Zn-Mg-Al-La-LDHs/SRF的极限氧指数(LOI)可达32.8%。改性前后SRF燃烧残余物表面形成致密保护炭层,其中添加量为5%(质量分数)的Zn-Mg-Al-La-LDHs/SRF的炭层更加致密。与未添加阻燃剂的SRF相比,含5%Zn-Mg-Al-La-LDHs/SRF的热释放速率峰值(PHRR)和烟释放率峰值(PSPR)分别降低了56.53%和59.52%。Zn-Mg-Al-LDHs与Zn-Mg-Al-La-LDHs均提高了SRF的热稳定性,当两者添加量为5%,SRF材料的残余炭渣率分别提升了15.69%和10.84%。

The flame retardant samples of hydrotalcite(Zn-Mg-Al-LDHs)and rare earth-containing La-modified hydrotalcite(Zn-Mg-Al-La-LDHs)flame retardant were prepared by coprecipitation method.The characteristics were analyzed by XRD and SEM-EDS.The simultaneous thermal analyzer,limit oxygen index and the cone calorimeter test were adopted to learn the effects of hydrotalcite and rare earth-containing La-modified hydrotalcite flame retardants on the flame retardancy and smoke suppression performance of silicone rubber foam(SRF).The result show that Zn-Mg-Al-LDHs and Zn-Mg-Al-La-LDHs have been successfully producted.Furthermore,by adding both to SRF,the vertical combustion grades reach to the V-0 level.When the addition amount raises to 20%,the limiting oxygen index(LOI)of Zn-Mg-Al-La-LDHs/SRF is up to 32.8%.A dense protective carbon layer is formed on the surface of the SRF combustion residue before and after the modification.In particular,the carbon layer of 5%-added Zn-Mg-Al-La-LDHs/SRF is denser.Compared to SRF without flame retardant,the peak of heat release rate(PHRR)and smoke release rate(PSPR)with added 5%Zn-Mg-Al-La-LDHs are reduced by 56.5%and 59.5%,respectively.Both Zn-Mg-Al-LDHs and Zn-Mg-Al-La-LDHs improve the thermal stability of SRF.When the mass fraction of both is 5%,the rate of residual carbon residue of the SRF is increased by 15.69%and 10.84%,respectively.