Structure and mechanical properties of triblock copolymer poly[styrene-block-(ethylene-co-propylene)-block-styrene] and asphalt mixture

Structure and mechanical properties of the mixtures of asphalt and the trib lock copolymer poly [styrene-block- (ethylene-co-propylene) -block-styrene] (SEPS) were studied by differential scanning calorimetry (DSC), needle pen etration and softening point, and tensile strength measurements. From the m easurements of glass transition temperature in the mixture of asphalt compo nents and SEPS, maltene, the soluble fraction extracted from the asphalt in heptane, was partially miscible with the ethylene/ propylene block of SEPS , whereas asphaltene, the insoluble fraction in heptane, partially miscible with the polystyrene block. The mixture of asphalt and SEPS was a partiall y miscible system. The viscosity, needle penetration and tensile strength o f the mixtures may be improved in the low concentration of SEPS(e.g. 5-10 w t%). A microstructure model of SEPS-asphalt blend system with the lower amo unt of SEPS was proposed and efficaciously approached to explain the result ing phenomena. The small amount of SEPS in asphalt seem to act as a compati bilizer and emulsify the two components of asphalt to make a mechanically s table network.