The tensile properties of the blends containing neat acrylonitrileÈ butadieneÈstyrene (ABS), styreneÈacrylonitrile (SAN) and the sodium sulphonated SAN ionomer have been investigated as a function of ion content of the ionomer in the blend. The tensile toughness and strength of the blends showed maximum values at a certain ion content of the ionomer in the blend. This is attributed to the enhanced tensile properties of the SAN ionomer by introduction of ionic groups into SAN and the interfacial adhesion between the rubber and matrix phase in the blend. The interfacial adhesion was quantiÐed by NMR solid echo experiments. The amount of interphase for the blend containing the SAN ionomer with low ion content (3É1 mol%) was nearly the same as that of ABS, but it decreased with the ion content of the ionomer for the blend with ion content greater than 3É1 mol%. Changing the ionomer content in the blends showed a positive deviation from the rule of mixtures in tensile properties of the blends containing the SAN ionomer with low ion content. This seems to result from the enhanced tensile properties of the SAN ionomer, interfacial adhesion between the rubber and matrix, and the stress concentration e †ect of the secondary particles.
1998 SCI.