纳米ZnSn(OH)_6对软质PVC阻燃和抑烟性能的影响

Influences of Nano ZnSn(OH)_6 on Flame Retardancy and Smoke Suppression of Flexible Polyvinyl Chloride

分别采用氧指数法、烟密度测试、热重分析和扫描电镜分析等评价了纳米羟基锡酸锌颗粒对软质PVC阻燃和抑烟性能的影响。在质量分数为1%-8%的范围内,纳米羟基锡酸锌的阻燃和抑烟效果均优于微米羟基锡酸锌。其中,添加纳米羟基锡酸锌质量分数为1%时,氧指数由27.1%提高到29.5%;添加质量分数为6%时,烟密度等级由88降到81。热重分析表明,纳米羟基锡酸锌的加入使软质PVC的残炭量在400℃以后均高于微米羟基锡酸锌,550℃时比微米羟基锡酸锌提高了4.3%,比空白PVC提高了6.4%。扫描电镜观察发现,添加纳米羟基锡酸锌的PVC燃烧残渣明显呈膨胀状态,结构最密实,起到了较好的隔氧、隔热及抑制可燃性气体逸出的作用。对试样的部分力学性能测试结果表明,添加纳米羟基锡酸锌的PVC试样的拉伸强度和断裂伸长率也有所改善,添加量在质量分数为4%时的效果最好。

The influences of nano ZnSn （OH）s particles in flexible polyvinyl chloride （PVC） on the flame retardancy and smoke suppression of it were studied by means of limiting oxygen index（ LOI）, smoke density test, thermogravimetry analysis （TGA） and SEM. The effects of nano ZnSn （OH） 6 on the flame retardancy and smoke suppression are both better than those of the micron ones between 1% and 8% mass fractions of nano ZnSn （OH） 6. The value of LOI increased from 27. 1% to 29.5 % when flexible PVC was filled with 1% nano ZnSn （OH）6. The smoke density rating decreased from 88 to 81 when 6% nano ZnSn（OH） 6 was doped. The TGA indicated that the char yields of flexible PVC samples filled with nano ZnSn （OH） 6 were all higher than those of the samples filled with micron ones at 400℃. The char yield of flexcible PVC filled with nano ZnSn（OH）6 was 4. 3% higher than that of flexcible PVC filled with micron ones at 550 ℃ and was 6. 4% higher than that of blank flexible PVC at the same temperature. The SEM proved that the morphology of char formed after combustion of the samples filled with the nanoparticles showed obviously bulgy state with a densi- fled structure, which can inhibit O2 and heat and combustion gases to go into the PVC bulk. The study of some mechanical properties of the samples verified that the tensile strength and elongation at break were also improved, the best effect was obtained at 4% nano ZnSn（OH） 6.