Effect of electron beam radiation on tensile and viscoelastic properties of styrenic block copolymers

The effect of electron beam (E-beam) radiation on a series of styrenic block copolymers (SBCs) was investigated. These SBCs included newly developed poly(styrene-block-isoprene/butadiene-block-styrene) (SIBS), poly(styrene-block-butadiene-block-styrene) (SBS), and poly(styrene-block-isoprene-block-styrene) (SIS). The tensile properties, stress relaxation, molecular weight, and dynamical mechanical properties were studied. Generally, the crosslink density and tensile moduli of SBCs increased with increasing of E-beam radiation dose. The tensile strength of SIBS and SIS was shown to first decrease at lower E-beam radiation dose (\u3c120 kGy) and then increase at higher radiation dose (\u3e190 kGy). The tensile strength of SBS was significantly decreased at high E-beam radiation dose (\u3e190 kGy). This was attributed to the differences between entanglement before E-beam radiation and the homogeneity of the crosslink network after exposure. POLYM. ENG. SCI., 54:2979–2988, 2014. © 2014 Society of Plastics Engineer