Effect of injection molding on structure and properties of poly(styrene-ethylene-butylene-styrene) and its nanocomposite with functionalized montmorillonite

摘要

In this paper, the effects of injection molding on structure and properties of poly(styrene-ethylene-butylene-styrene) (SEBS) and its nanocomposite with a functionalized montmorillonite (FMMT) were illustrated by comparison with the results of hot pressing. The injection-molded SEBS and its FMMT nanocomposite have a skin-core morphology with FMMT platelets more preferentially aligned along the sample plane, while hot-pressed samples not. The injection-molded samples also have a dense structure, and a less extent of microphase separation. In the injection molding process, the high shear flow coupled with solidification in presence of temperature gradient and high pressure in the closed cavity greatly affect the morphology and structure of the SEBS and its nanocomposites. The results also indicate attractive interaction between the soft segments of SEBS and the long alkyl silane chain grafted to FMMT, which allows FMMT to form a macroscopic network structure after the high-speed and high-pressure injection molding. The SEBS/FMMT-injected nanocomposite have the highest tensile strength and the best corrosion resistance, which can be attributed to the dense skin-core structure, stronger SEBS/FMMT interaction and the preferentially aligned FMMT platelets.