A method of producing a synthetic polymer blend comprising steps of (i) blending a styrene-butadiene-styrene thermoplastic elastomer (SBS) with a compatibilizer selected from the group consisting of polybutadiene grafted polystyrene resin (HIPS), styrene-hydrogenated-butadiene-styrene (SEBS) and poly-dimethyl-phenylene-oxide (PPO), and dispersing particles of said SBS to a mean particle size of substantially 3 microns or less in diameter, to form an intermediary ingredient, wherein.times..times..times..times..times..times..times..times..times..ti- mes..times..times. ##EQU00001## is substantially ##EQU00002## to 4; and (ii) blending the intermediary ingredient in the step b) with further ingredient(s) including at least general purpose polystyrene (GPPS), and further dispersing the SBS particles, to form the synthetic polymer blend, wherein.times..times..times..times..times..times..times..times..ti- mes..times..times..times..times..times. ##EQU00003## is substantially.times..times..times..times. ##EQU00004##