Synthesis Of Molybdate/LDH Hybrids And Study On Their Flame Retardant Effect In PP Matrix

Inorganic flame retardants not only have flame retardant effect in the composites, but also inhibit the generation of smoke and hydrogen chloride, given the materials non-toxic and non-corrosive, so get widely used. In order to combine the reinforcement effect of transition metal compounds and layered compounds, three different transition metal molybdates were synthesized and incorporated to ABS to study their flame retardant and smoke suppression effect; then layered double hydride (LDH) synthesized with ethanol as solvent was incorporated into PP to study its flame retardant effect on PP; finally, molybdates/LDH hybrids were prepared by hydrothermal process, and a series of experiments were conducted to compare the flame retardant effect of hybrids and single component. The detailed outlines are elaborated as follows:1. The well-crystallized and uniformed molybdates were prepared by hydrothermal method, and then incorporated into ABS matrix by masterbatch melting method. The molybdates disperse well in the matrix and have good interfacial adhesion with PP. Incorporation of molybdates into ABS could decrease the initial decomposition temperature of ABS, improve the amount of carbon residue, and can reduce the values of peak of heat release rate and the total heat release. Molybdates can also reduce the amount of smoke release of ABS, which is related to molybdates promoting the degradation of ABS, the increasing of the carbon residue can isolate the release of heat and smoke. The results show CuMoO4has the best effect among the three molybdates.2. Zn-Al layered double hydride was synthesized with ethanol as solvent, then the temperature was rise to100degree, so that the interlayer of alcohol molecule evaporate to strut the LDH layers, in this way, exfoliated LDH was obtained. The exfoliated LDH was then incorporated into PP to prepare PP nanocomposites by masterbatch melting method. LDH layers disperse well in the matrix, and enhance the thermal stability of PP significantly, the initial decomposition temperature increased by more than50degree, the mechanical tests shows that the energy storage modulus and elongation at break were increased, the cone calorimeter results show that the heat release quantity and total heat release quantity were all decreased, but the effect is not better than the modified double hydroxide. 3. On the basis of previous work, molybdate/LDH hybrids were prepared through the hydrothermal and ion exchange method, well-dispersed hybrids/PP nanocomposites were prepared by masterbatch melting method. Experimental results indicate hybrids can improve the thermal stability of polymer as well as decrease the PHRR and THR values more effectively than single component, which prove the synergistic effect between molybdate and LDH. The characterization of carbon residue indicates the incorporation of molybdate-LDH hybrids can increase the degree of graphitization of the carbon residue, it is beneficial for suppressing the heat release and smoke release. The results also show that molybdate/LDH hybrids have much application value as the enhancer for polymers to improve the thermal stability and flame retardant performance.