Structure and properties of SEBS/PP/OMMT nanocomposites
(1.Department of Materials Science and Engineering, Shanghai Institute of Technology, Shanghai 200235, China2.Chemistry Department, East China Normal University, Shanghai 200062, China)
Abstract: Nanocomposites based on styrene-b-(ethylene-co–butylenes)-b-styrene triblock copolymer(SEBS), polypropylene (PP) and organomontmorillonite (OMMT) were prepared using melt intercalation by a twin mill. The nanostructure of SEBS/PP/OMMT hybrids was characterized by X-ray diffractometry(XRD) and transmission electron microscopy(TEM). The d001 space of OMMT and SEBS/PP/OMMT hybrid increases from 1.30 nm to 3.52 nm and 4.06 nm, respectively which indicate, that the C16 and SEBS/PP could intercalate in the silicate layers and expand the basal spacing. The formation of intercalated structure was also confirmed by TEM. The results show that the individual silicates are well dispersed in the elastomer matrix. The glass transition temperature (tg) of PS block of SEBS was investigated by dynamic mechanical analysis (DMA). It is shown that there are remarkable enhancements in tg of PS block containing a small mass fraction of OMMT. tg of PS in SEBS of the nanocomposites has been increased about 39 ℃ when containing 4% OMMT. The influence of OMMT on the dynamic storage moduli is temperature dependent. Below 50 ℃ the SEBS/PP/OMMT composites with higher OMMT contents show higher dynamic storage moduli. OMMT has the function of reinforcing SEBS/PP elastomers. However, the influence of OMMT on the mechanical properties of the nanocomposites is not significant according to the tensile test and tear test.
Key words: SEBS; polypropylene; organomontmorillonite; nanocomposites