Effect of intercalant types on the properties of melt blended metallocene polyethylene/metallocene polyethylene-g-silane/clay nanocomposites

Melt mixed metallocene-catalyzed polyethylene elastomer (mPE)/clay nanocomposites, using a functionalized polyolefin elastomer (mPE-g-silane) as a compatibilizer, with the addition of the commercial clay with different intercalant types (Cloisite 20A and 30B) were prepared to investigate the importance of interfacial interaction. Cloisite 30B gave a relatively higher polarity than Cloisite 20A, but smaller original d-spacing. According to X-ray diffraction (XRD) and transmission electron microscopy (TEM) results, Cloisite 20A-filled nanocomposites depicted fairly well-dispersed clay within the mPE matrix, except with higher clay content. By contrast, the clay agglomerates were evident for Cloisite 30B-filled cases. A continuous increase of gel content for Cloisite 20A-filled systems was observed, but only a limited variation for Cloisite 30B-filled systems was found. The roles of the polarity degree of the organically modified clay, original d-spacing, and the compatibilizer, were quite essential. Young's modulus of Cloisite 20A-filled samples increased with increasing clay content, from 23.8 +/- 1.3 MPa [0 parts per hundred resins (phr)] to 34.1 +/- 2.0 MPa (9 phr), whereas modulus of Cloisite 30B-filled samples did not show a significant variation. The tear strength of Cloisite 20A-filled nanocomposites increased up to two-fold with increasing clay content, reaching 9 phr. Only a slight increase in tear strength of Cloisite 30B-filled nanocomposites was observed. For the cutting strength, Cloisite 20A-filled cases also conferred higher values in comparison with Cloisite 30B-filled cases.