改性水滑石对聚丙烯阻燃和力学性能的影响

Effect of Modified Hydrotalcite on Flame Retardant and Mechanical Properties of Polypropylene

摘要:

以硝酸镁和硝酸铝为原料，采用共沉淀法制备了Mg/Al-CO3-LDHs前体，然后通过阴离子交换法制备了衣康酸插层、钛酸酯偶联剂NDZ-201附着的复合改性水滑石（ITA-LDHs）。通过熔融共混法制备了阻燃性能和力学性能较好的聚丙烯(PP)复合材料。通过FTIR，XRD，TGA和SEM对ITA-LDHs进行了表征。结果表明衣康酸已经插入到水滑石层间，钛酸酯偶联剂已经附着在水滑石表面。通过测量复合材料的极限氧指数(LOI)，垂直燃烧实验(UL-94)，热重曲线，热释放速率（HRR），总热释放速率（THR）和质量损失率表明：随着水滑石添加量的增多，无论是未改性还是改性的LDHs都能对PP起到阻燃效果，且改性后的LDHs的LOI值、抗熔滴时间、热稳定性、成炭率均显著提高。当水滑石的添加量30%[计算公式请在修回说明中给出。]（以100g聚丙烯的质量为基准）[以100g聚丙烯的质量为基准]时，ITA-LDHs的LOI达到27.5%，明显优于未改性的25.5；UL-94等级达到V0级，优于未改性的V1级；通过测试材料的弯曲强度和拉伸强度可知，与未改性的水滑石相比，改性后的水滑石力学性能明显改善。

Abstract:

Mg/Al-CO3-LDHs precursors were prepared by coprecipitation method from magnesium nitrate and aluminium nitrate, and then the composite modified hydrotalcites (ITA-LDHs) with the itaconic acid intercalation and titanate copling agent NDZ-201 was prepared by anion exchange method. Polypropylene (PP) composites with good flame retardancy and good mechanical properties were prepared by melt blending. The structure of ITA-LDHs were characterized by FTIR, XRD, TGA and SEM. The results showed that the CO32- was replaced partly by itaconic acid, titanate coupling agent was attached on the surface of hydrotalcites. The limit oxygen index(LOI), vertical burning test(UL-94),TGA , HRR, THR and mass loss rate indicated that with the increase of the addition of hydrotalcites, both unmodified and modified LDHs can play a flame retardant effect on PP, and the modified LDHs effect is better than that of the unmodified LDHs. When the addition of hydrotalcites are 30% (based on the quality of 100g polypropylene), the LOI value of ITA-LDHs reaches 27.5%, which is significantly better than that of the unmodified 25.5%, and the UL-94 grade reaches V0 level, which is better than that of the unmodified V1 grade. By testing the bending strength and tensile strength of the material, it can be seen that the mechanical properties of the modified hydrotalcites are obviously improved compared with the unmodified hydrotalcite.