EFFECT OF STYRENE-BUTADIENE-STYRENE BLOCK-COPOLYMER ON DYNAMIC-MECHANICAL PROPERTIES OF HIGH-IMPACT POLYSTYRENE

For the selection of the polymer materials and polymer blends for vari ous fields of applications, dynamic-mechanical properties, the primary viscoelastic functions as well as the stability of materials on diffe rent loads are very important. Since polymer materials are viscoelasti c, their mechanical properties are dependent on temperature and time. The dynamic-mechanical properties of high-impact polystyrene, (PS-HI) and blends of PS-HI and styrene-butadienestyrene block copolymer, (SBS ) were investigated. Under the conditions of dynamic-mechanical load, the investigated systems will have different behavior due to the vario us content of the hard phase, polystyrene and soft phase, polybutadien e. The investigations were done by DMA analysis. The primary viscoelas tic functions were determined. The influence of the constant stress on the strain and moduls at various temperatures was examined. The effec ts of the time on moduls changes was obtained by generating the master curves. The viscoelastic functions and the stability on the constant load, the changes of the moduls with time and temperature depend on th e amount of polystyrene in the examined copolymers and blends. This in vestigation presents the possibility of predicting a useful lifetime o f materials.