Investigation of Aging Behavior and Thermal Stability of Styrene-Butadiene-Styrene Tri-block Copolymer in Blends

Aging behavior and thermal stability of styrene-butadiene-styrene tri-block copolymer (SBS) in blends were investigated using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and thermo-gravimetric analysis (TG). From the analysis of FTIR, the alcohol and carboxyl hydroxyl groups will be gradually generated during the thermal and ultraviolet aging, and the effect of short-term high temperature is more serious than longterm ultraviolet exposure on the structure of SBS; XPS results show that oxygen/carbon ratio of thermal and ultraviolet aged SBS have significantly increased, while the relative concentration of C-O-H(R) is far higher than that of COOH(R); inferred oxidation mechanism of SBS based on the analytical results of FTIR and XPS shows alcohol, carboxyl, ether, ketone, etc. have mainly formed in blends after thermal or ultraviolet aging; moreover, on account of the distribution index of carbon-oxygen binding state of thermal and ultraviolet aged SBS(respectively 3.15 and 1.28), C-O is easily produced than C=O and the effect of thermal aging is more obvious; from the results of TG, the maximum decomposition rate and temperature decrease after aging.