Naslov
Dynamic Mechanical Behaviour of Styrene/Butadiene Copolymers and their Blends

Autori
Rek, Vesna ; Holjevac Grgurić, Tamara ; Jelčić, Želimir ; Hace, Drago

Izvornik
Macromolecular symposia (1022-1360) 148 (1999); 425-436

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
PS-HI copolymer ; SBS copolymer ; PS-HI/SBS blends ; dynamic mechanical properties ; creep modulus ; master curve

Sažetak
The dynamic mechanical behaviour of high impact polystyrene (PS-HI), styrene/butadiene/styrene block copolymer (SBS) and PS-HI+SBS blekds were investigated. Dynamic mechanical analysis (DMA) was performed in the temperature range -100 C to 100 C. The primary viscoelastic functions were determined. The copolymers PS-HI and SBS as well as PS-HI+SBS blends were investigated in creep- fatigue regime and relaxation at temperatures 15, 30, 35, 40 and 45 C. Dynamic mechanical behavior of PS-HI, SBS and PS-HI+SBS blends depends on the copolymer and blends composition, the hard phase content, time and temperature. With the decrement of the hard phase PS concentration, the loss tangent of the soft phase increases while the loss tangent of the hard phase and the storage modulus decrease. All samples have a single Tg of the hard phase and a single Tg of the soft phase. The glass transition temperatures decrease as the content of the PS phase decreases. At the constant load the creep values increase and those of creep modulus decrease over a period of time, for all examined samples. These effects are more pronounced in samples with lower content of hard phase and a higher temperatures. The time-temperature correspondence principle was applied to create master curves for the reference temperature 25 C for the creep modulus of PS-HI, SBS and PS-HI+SBS blends on a time scale far outside of the range measured by DMA experiments. These results enable us to predict the useful life of our copolymers and their blends in a widge range of time and temperature.

Izvorni jezik
Engleski

Znanstvena područja
Kemijsko inženjerstvo

Napomena
Glavni autori: Tamara Holjevac Grgurić, Vesna Rek

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