Polyethylene/clay melt compounding

The influence of the inclusion size, shape, and surface treatment on the gas permeability of polyethylene in its micro- and nanocomposites has been investigated in various papers.Kato et al. report the N2 permeability of nanocomposites based on polyethylene (PE) melt compounded with maleic anhydride grafted polyethylene (MA-g-PE) and octadecylamine (C18-MMT) modified montmorillonite. The gas permeability coefficient for all the prepared samples are reported in Fig. 11.8. Interestingly, polyethylene, maleic anhydride grafted polyethylene, a 70/30 blend of PE/MA-g-PE and a blend of PE/MA-g-PE/MMT have almost the same permeability coefficient. Only the composites obtained by mixing the polymeric matrices with the modified montmorillonite show for PE/MA-g-PE/C18-MMT (PECHl) a decrement of 30% in permeability and for MA-g-PE/C18-MMT (PECH3) a decrement of 35%. The differences in the gas barrier property were attributed to the different dispersion of the clay silicate layers in the matrix. 

Hotta and Paul [31] reported studies on melt compounding of many different organoclays into linear low density polyethylene and found that in some cases a 5% clay loading resulted in a 153% increase in modulus. The TEM images confirmed that the clay was largely exfoliated. 

HDPE/bamboo composites with different nanoclay and maleated polyethylene (MAPE) contents were fabricated by melt compounding. The compounding characteristics, clay dispersion, HOPE crystallization, and mechanical properties of the composites were studied. The X-ray diffraction (XRD) data showed that the clay was exfoliated only when 1% clay was added to pure HOPE wifliout MAPE. For HDPE/bamboo systems, MAPE was necessary to achieve clay exfoUatiOTi. For the HDPE/bamboo fiber composites, tensile strength, bending modulus, and strength were improved with the use of MAPE however, the use of the clay in the system led to reduced mechanical properties [27]. 

Polyolefins and chlorine-containing polymers were investigated to produce polymer nanocomposites. Natural and oiganic-treated montmorillonite clays were melt compounded with the polymers. Oiganic-treated montmorillonite clay dispersed well in polychloroprene, chlorinated-polyethylene, polyvinyl chloride, chlorinated-... 

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