The relationship between molecular structure and the effect of coupling agents in flame-retardant ABS blends

摘要

Tetrabromobisphenol A and antimony trioxide were used as flame-retardant additives in flame-retardant acrylonitrile-butadiene-styrene (FR-ABS) blends. Four types of coupling agents, LICA 38, LICA 44, NZ 38, and SMA-g-L44, were employed to improve the physical properties of the blends by inorganic surface treatment. The molecular structures of these coupling agents differ from each other in the polymer binding functional groups (PB groups), the central tetravalent metal, and the molecular weight. The octyl molecular segments in the PB groups of the coupling agents are advantageous to the tensile strength and elongation of FR-ABS. The high-MW coupling agents, SMA-g-L44 copolymers, provide the highest impact resistance and elongation of all. The coupling agent with the central metal Zr brings better tensile properties to FR-ABS than Ti does; however, Zr will slightly decrease the LOI of FR-ABS. All the coupling agents are able to lower the glass transition temperature and increase the thermal resistance of FR-ABS blends. Finally, the disappearance of both voids and the interfacial boundary are clearly observed in scanning electron microscope (SEM) photographs.