Effect of an Ultrahigh Rubber ABS Impact Modifier Resin on Mechanical Properties of Intumescent Flame-Retardant ABS Composites

The effect of an ultrahigh rubber acrylonitrile-butadiene-styrene (ABS) impact modifier resin (UHR-ABS) on the mechanical properties of an intumescent flame-retardant ABS composite was characterized. Samples were obtained by compounding ABS and an intumescent flame-retardant master batch that was prepared using an intumescent flame-retardant composite (IFRC) with ABS and/or UHR-ABS as well as by direct compounding IFRC, UHR-ABS, and ABS. The incorporation of UHR-ABS resulted in reduction in the storage modulus, damping behavior and glass transition temperature, as evidenced by dynamic mechanical analysis. With increasing mass fraction of the UHR-ABS, the tensile strength and the flexural strength decreased gradually, and the notched impact strength increased, but the increase was more significant for compounding IFRC, UHR-ABS, and ABS than for compounding ABS and IFRC master batches. SEM micrographs of the fresh fracture surface of the composites were used to estimate the mechanism of the increased notched impact strength owing to the incorporation of UHR-ABS.