三氧化钼复合抑烟阻燃硬质PVC裂解性能研究

Flame Retardance,Smoke Suppression and Pyrolysis of Rigid PVC Modified by Molybdenum Trioxide Composite

研究了三氧化钼(MoO_3)、硼酸锌(ZB)和聚磷酸铵(APP)的用量和配比对硬质PVC抑烟阻燃性能的影响；抑烟阻燃组分对材料裂解产物的影响,并探讨了抑烟阻燃机理。结果表明,MoO_3、ZB和APP的用量分别为3%、1%和10%时,PVC材料的最大烟密度由100降低到72．5,烟密度等级由87．7降低到53．2,氧指数由43．0%提高到58．0%。热失重和高温裂解色质联用色谱分析结果表明,没有经过改性的PVC在失重第一阶段不但脱去大量的HCl气体,使大分子主链形成较长的顺式共轭结构,而且该共轭链在裂解温度下发生了较多的环化反应,生成大量的苯、萘、茚等芳香族化合物及其同系物。MoO_3-ZB-APP组分明显促进了PVC脱去HCI的反应,使共轭分子链主要形成不易发生环化反应的反式结构,显著减少了芳香化合物有害气体的生成,使材料的发烟量降低。

The influences of molybdenum trioxide（MoO3）, zinc borate（ZB）, and ammonium polyphosphate（APP） on the smoke suppression and flame retardance of PVC were investigated. When the weight percentages of MoO3, ZB, and APP in PVC were 3 %, 1%, and 10%, respectively, the smoke suppression and flame retardance were greatly improved. The mechanism of decomposition of PVC was studied. During the decomposition, PVC releases HCl and forms a cis-conjugated structure, aromatic compounds such as benzene, toluene and naphthalene were generated at 350℃ through cyclization. The MoO3-ZB-APP system obviously accelerated the release of hydrogen chloride leading to a trans-non-conjugated structure, thus inhibited the formation of aromatic compounds.