Thermal stability of styrene–(ethylene butylene)–styrene-based elastomer composites modified by liquid crystalline polymer, clay, and carbon nanotube

Abstract

The thermal decomposition behaviors of styrene–(ethylene butylene)–styrene (SEBS) thermoplastic elastomer filled with liquid crystalline polymer (LCP), organomontmorillonite (OMMT), and carbon nanotube (CNT) as a heat stabilizing filler, were comparatively investigated using nonisothermal- and isothermal-thermogravimetric analyses in air. The isoconversional method was employed to evaluate the kinetic parameters (Ea, lnA, and n) under dynamic heating. For neat samples, OMMT and CNT exhibited their respective lowest and highest thermal stabilities as revealed from the lowest and the highest Tonset values, respectively. The decomposition rates of the composites containing OMMT at the temperature >250 °C were higher than those containing CNT and LCP, respectively, whereas the elastomer matrix degraded with the highest rate. The obtained TG profiles and calculated kinetic parameters indicated that the incorporation of LCP, OMMT, and CNT into elastomer matrix improved the thermal stability. Especially, the CNT- and OMMT-containing composites significantly improved the thermal stability compared with the neat matrix polymer. Simultaneously recorded DSC thermograms revealed that the degradation processes for the neat polymers and their composites were exothermic in air. From the simultaneously recorded DSC data, the enthalpy of thermal decomposition for each composite system was found to be lower than that of the neat matrix and mostly decreasing with increasing filler loading. The isothermal decomposition stabilities of the neat SEBS and its composites containing the different fillers were in agreement with those of the nonisothermal investigation.