Polyethylene/clay dispersion

Uses Wetting agent, detergent, penetrant, emulsifier for metal cleaners, l l, household, and hand cleaners, textile processing, clay soils, firefighting prods. emulsifier for polyethylene emulsions dispersant solubilizer defoamer... 

Durmus, A., Kasgoz, C., and Macosko, W. 2007. Linear low density polyethylene (LLDPE)/ clay nanocomposites. Part I-Stmctural characterization and quantification of clay dispersion by melt rheology. Polymer 48 4492-4502. 

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]. 

K. Stoeffler, P. G. Lafleur, and J. Denault, Effect of intercalating agents on clay dispersion and thermal properties in polyethylene/montmorillonite nanocomposites. Polymer Engineering and Science, 48 (2008), 1449-66. 

Lee, Y. H., T. Kuboki, C. B. Park, M. Sain, and M. Kontopoulou. 2010. The effects of clay dispersion on the mechanical, physical and flame-retarding properties of wood fiber/ polyethylene/clay nanocomposites. JAppl Polym Sci 118 452-61. 

Sanchez-Valdes S., Lopez-QuintanillaM. L., Ramirez-Vargas E., Medellin-Rodriguez F. J. and Gutierrez-Rodriguez J. M., Effect of ionomeric compatibilizer on clay dispersion in polyethylene/clay nanocomposites , Macromol Mater Eng, 2006, 291, 128-136. 

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-... 

S. Sanchez-Valdes, J. Mendez-Nonell, F. J. Medellin-Rodriguez, E. Ramirez-Vargas, J. G. Martinez-Colunga, H. Soto-Valdez, L. Munoz-Jim nez, and G. Neira-Velazquez, Effect of PEgMA/amine silane compatibihzer on clay dispersion of polyethylene-clay nanocomposites, Polym. Bull. 63(6), 921-933 (December, 2009). 

Available Forms. Phthalocyanines are available as powders, in paste, or Hquid forms. They can be dispersed in various media suitable for aqueous, nonaqueous, or multipurpose systems, eg, polyethylene, polyamide, or nitrocellulose. Inert materials like clay, barium sulfate, calcium carbonates, or aluminum hydrate are the most common soHd extenders. Predispersed concentrates of the pigments, like flushes, are interesting for manufacturers of paints and inks (156), who do not own grinding or dispersing equipment. Pigment—water pastes, ie, presscakes, containing 50—75% weight of water, are also available. 

Solution blending Polar as well as nonpolar solvents can be used in this method. The polymer is solubilized in a proper solvent and then mixed with the filler dispersion. In solution, the chains are well separated and easily enter the galleries or the layers of the fillers. After the clay gets dispersed and exfoliated, the solvent is evaporated usually under vacuum. High-density polyethylene [24], polyimide (PI) [25], and nematic hquid crystal [26] polymers have been synthesized by this method. The schematic presentation is given in Scheme 2.2. 

The incorporation of unmodified and organically modified montmorillonite nanoclays (namely 15A and 30B) in chlorinated polyethylene (CPE) by the solution intercalation method and their influence on mechanical properties of the nanocomposites have been studied by Kar et al. [137]. The o-MMT-embedded nanocomposites show enhanced tensile strength and Young s modulus in comparison to the nanocomposites containing the unmodified nanoclay. They have shown from and XRD analyses that organically modified clay shows better dispersion in the CPE matrix. This has been further substantiated from FTIR analysis, which proves an interaction between the CPE matrix and the clay intercalates. 

As an inorganic mineral, most unmodified nanoadditives are strongly hydrophilic and are generally compatible and miscible only with a few hydrophilic polymers, for instance, clay can only be made into PNs with polyethylene oxide),27 poly(vinyl alcohol),28 and a few other water soluble polymers. Most polymers are hydrophobic and thus they are neither compatible nor miscible with the unmodified nanoadditives, leading to an inability to achieve a PN with a good nanodispersion in most cases. Therefore, for most nanoadditives that have been used to prepare the PNs, an important and necessary feature is their surface treatment that provides compatibility to the nanoadditives and enables them to be uniformly dispersed (and/or separated into single nanoparticles) in the polymer matrix. 

There are two basic types of nanocomposites, in which particles are intercalated or exfoliated. In an intercalated composite the nanodispersed filler still consists of ordered structures of smaller individual particles, packed into intercalated structures. Exfoliated particles are those dispersed into practically individual units, randomly distributed in the composite. Layered silicates, such as montmorillonite clays or organoclays, can be used in nanocomposites. Because clays are hydrophilic and polyolefines are hydrophobic, it is not easy to make a nanocomposite based on polyethylene or polypropylene because of their natural incompatibility. 

Natural, unmodified montmorillonite-Na (MMT-Na) has cation exchange capacity, typically 80-90 mequiv/100 g. Although some polymers, such as polyethylene oxide or polyvinylpyrrolidone, are of sufficient polarity to be able to directly exfoliate unmodified MMT-Na, organic modification of the layered clay is usually required to render the hydrophilic surface of the clay more hydrophobic and thus more compatible with most polymers, thereby improving the wettability and dispersibility of the clay in the polymer matrix. 

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