杂多酸对杨木燃烧过程中热/烟释放行为的影响

Effects of heteropolyacids on the heat/smoke release behavior during poplar wood combustion

对比经H3PMo12O40(PMA)、H3PW12O40(PTA)、H3SiW12O40(TSA)等杂多酸浸渍的杨木粉的热解过程和热、烟释放特性参数,探究杂多酸对杨木热解过程的影响及其作用机制。利用热重分析仪(TGA)、锥形量热仪(CONE)研究3种杂多酸对杨木粉热解TG、DTG曲线、热释放速率(HRR)、总热释放速率(THR)、生烟速率(SPR)和总烟释放量(TSP)等参数的影响;并采用FT-IR红外光谱和拉曼光谱表征高温残炭的结构。TGA结果表明,3种杂多酸均可有效降低杨木热解的Ti、Tmax、Rmax并提高CR740℃,其中,S-wood/PMA具有最低的最大热失重温度(Tmax)及最大热失重速率(Rmax)较S-wood分别降低了17.5%和23.3%,而S-wood/PTA在740℃时热解炭残余量(CR740℃)最高,其次是S-wood/TSA;CONE结果表明,杂多酸/杨木试样的HRR、THR、SPR、TSP以及COY等参数有显著地降低,S-wood/PMA具有最低的热、烟释放参数,其最高释热峰峰值(PHRR)和THR较S-wood分别降低了31.6%、67.5%,SPR和TSP较S-wood分别降低了86.0%,87.5%。FT-IR及Raman分析显示,杂多酸/杨木试样残炭中缔合O—H和不饱和CC含量明显增加,并有酯键和MoO3、WO3、SiO2等化合物存在,同时AD/AG有所减小。因此,杂多酸通过高温分解催化杨木脱水成酯、固化成炭,有效地降低杨木粉的热解速率,延缓热解过程,表现出良好的阻燃和高效的抑烟作用。其中,H3PMo12O40对杨木粉的阻燃、抑烟效果最佳。

In this paper,the effects of heteropolyacids on pyrolysis process of poplar powder and its mechanism were studied by comparing the pyrolysis process and characteristic parameters of heat and smoke release of poplar powder treated with H 3PMo 12 O 40(PMA),H 3PW 12 O 40(PTA)and H 3SiW 12 O 40(TSA).The TG and DTG curves of samples were determined by thermogravimetric analyzer.And the heat release rate(HRR),total heat release(THR),smoke produce release(SPR)and total smoke produce(TSP)were measured by cone calorimetry(CONE).Besides,the FT-IR and Raman spectrometers were used to characterize the residual char.TGA results showed that three heteropolyacids could effectively decrease the initial pyrolysis temperature(T i),the maximum weight loss temperature(T max)and the maximum weight loss rate(R max)of poplar wood and increase the char yield at 740℃(CR 740℃).S-wood/PMA had the lowest T max and R max among all samples,which were decreased by 17.5%and 23.3%than S-wood,respectively.And S-wood/PTA had the highest CR 740℃,followed by S-wood/TSA.The CONE results showed that parameters of HRR,THR,SPR,TSP,and COY of the heteropolyacid/poplar samples were significantly reduced.S-wood/PMA also had the lowest parameters of heat and smoke release,whose peak heat release rate(PHRR)and THR were decreased by 31.6%and 67.5%and the TSR and TSP were 86.01%and 87.5%lower than those of S-wood,respectively.And FT-IR and Roman spectrums showed that the content of associated O-H and unsaturated C C in the residual char of the heteropolyacid/poplar samples were increased significantly,and ester bonds,MoO 3,WO 3 and SiO 2 formed.Furthermore,A D/A G of heteropolyacid/poplar samples was decreased.Therefore,heteropolyacids catalyze the dehydration of poplar powder into esters and the solidify of poplar powder into carbon by pyrolysis,which effectively slows down the pyrolysis rate and inhibits the pyrolysis process of poplar powder,exhibiting good flame retardancy and excellent smoke suppression effect.And H 3PMo 12 O 40 has the best flame retardant and smoke suppression effects on poplar powder among the three heteropolyacids.