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

Mg/Al-CO3-LDHs precursor was prepared by coprecipitation from magnesium nitrate and aluminium nitrate. And then composite modified hydrotalcite (ITA-LDHs) with itaconic acid intercalation and titanate coupling agent NDZ-201 was prepared by anion exchange method. Subsequently, polypropylene (PP) composites with good flame retardancy and good mechanical properties were prepared by melt blending. ITA-LDHs was characterized by FTIR, XRD, TGA and SEM. The results showed that itaconic acid was inserted into the interlayer of hydrotalcite, and titanate coupling agent was attached to the surface of hydrotalcite. The prepared composites were evaluated by limit oxygen index (LOI), vertical burning test (UL-94), TGA and cone calorimeter. The results indicated that with the increase of the addition of hydrotalcite, both unmodified and modified LDHs played flame-resistant effect on PP. The LOI value, anti-dripping time, thermal stability and carbonization rate of the composites containing modified LDHs were better than those of the composites containing unmodified LDHs. When the addition of ITA-LDHs in PP was 30% (based on the mass of PP, the same below), the LOI value reached 27.5% and the UL-94 grade reached V0 level, both were better than those of the composites adding unmodified hydrotalcite. By testing the bending strength and tensile strength of the composites, it was found that the addition of ITA-LDHs improved obviously the mechanical properties of the composites. © 2019, Editorial Office of FINE CHEMICALS. All right reserved.