Preferential melt intercalation of clay in ABS/brominated epoxy resin-antimony oxide (BER-AO) nanocomposites and its synergistic effect on thermal degradation and combustion behavior

ABS/organo montmorillonite (OMT) nanocomposites and ABS/brominated epoxy resin-antimony oxide (BER-AO)/OMT nanocomposites were prepared via melt compounding. The dispersion of OMT in nanocomposites was investigated by wide-angle X-ray diffraction and transmission electron microscopy. The results revealed an intercalated structure in ABS/OMT nanocomposites and the OMT layers mainly distribute in SAN phase. However, a completely exfoliated structure was found in ABS/BER-AO/OMT nanocomposites and OMT layers preferentially located in the BER phase which indicated that the OMT platelets had a much higher affinity with brominated epoxy resin than ABS resin. Based on the above morphological results, a schematic diagram of the ABS/OMT, ABS/BER-AO/OMT nanocomposites was established. The thermal degradation behavior was characterized by thermogravimetry. The results showed that the exfoliation of OMT can enhance the thermal stability of pure ABS resin and ABS/BER blends. An increase in the limited oxygen index (LOI) value was observed with the addition of OMT and it was found that such an enhancement is closely related to the morphologies of the chars formed after combustion. A synergistic effect between OMT and BER-AO during the combustion of the nanocomposites was found and a schematic mechanism was presented.