Thermal and thermo-oxidative behaviour of butadiene-styrene copolymers with different architectures

The thermal and thermo-oxidative behaviour of three types of styrene-butadiene (BS) copolymers namely (poly(styrene-b-butadiene-b-styrene) linear triblock copolymer, poly(butadiene-b-styrene)4 star block copolymer and a poly(butadiene-r-styrene) random copolymer) have been studied. It was shown by FT-IR, DSC and DMTA experiments that during the heating up to 200 °C, chain-scission and crosslinking reactions occur in all copolymers. The temperature interval over which this process occurs is larger and at higher temperatures for the random copolymer compared with the two block copolymers. The random copolymer proved to have the highest thermal stability due to the stronger interactions between the styrene and butadiene units. Concerning the thermal degradation/decomposition products, the three BS copolymers produce similar amounts of gases but different quantities of oils. The distribution of the compounds in BS degradation oil depends on the copolymer structure, while the residue structures are similar for all studied copolymers.