Phasenmorphologie und Relaxationsverhalten von SEBS/PP-Blends

Commercial thermoplastic elastomers based on styrene-ethylene/butylene-styrene block copolymers are complex blends containing inorganic fillers, plasticizers, additives, and as a thermoplastic polymer mostly polypropylene. Model compounds of SEBS and PP are investigated. It is shown that mechanical properties, thermal application limits and relaxation behaviour are determined by the phase morphology of the blends. Two methods are presented which were developed especially for the characterisation of thermoplastic elastomers. Intermittent stress strain measurements can be used to describe the strain recovery behaviour of the material. The relaxation behaviour can be studied by thermal scanning stress relaxation tests which also allow to draw conclusions concerning the phase morphology.