Polyethylene-based nanocomposites

C. Gorwade, F. Hughes, D. Cai, I.A. Ashcroft, V.V. SUberschmidth, M. Song, S. Shaw, Analysis of the high strain-rate behaviour of polyethylene based nanocomposites, Applied Mechanics and Materials 70 (2011) 237-242. 

Devendra R, Hatzkiriakos SG, Vogel R (2006) Rheology of metallocene polyethylene-based nanocomposites influence of graft modification. J Rheol 50 415-434... 

Dufresne et al. [153] noted that surface adsorption of potyojq ethylene chains on the surface nanocrystals can improve dispersibility and thermal stability of nanocrystals during the melt processing of polyethylene based nanocomposites. The chemical modification of cellulose is a most effective approach to avoid irreversible agglomeration during drying, and enhance the adhesion between nanocellulose and nonpolar matrices [132]. Dufresne et al. [98] showed also, that chemical and physical compatibilization imparted by poly(ethylene glycol) and polyoxyethylene layers promoted the interfacial interaction between cellulosic nanoparticles and polystyrene. 

Keywords Polyethylene-based blends, polyethylene-based composites, polyethylene-based nanocomposites, carbon nanotubes, lignocellulose... 

Broadband dielectric spectroscopy is a powerful tool to investigate polymeric systems (see [38]) including polymer-based nanocomposites with different nanofillers like silica [39], polyhedral oligomeric silsesquioxane (POSS) [40-42], and layered silica systems [43-47] just to mention a few. Recently, this method was applied to study the behavior of nanocomposites based on polyethylene and Al-Mg LDH (AlMg-LDH) [48]. The properties of nanocomposites are related to the small size of the filler and its dispersion on the nanometer scale. Besides this, the interfacial area between the nanoparticles and the matrix is crucial for the properties of nanocomposites. Because of the high surface-to-volume ratio of the nanoparticles, the volume fraction of the interfacial area is high. For polyolefin systems, this interfacial area might be accessible by dielectric spectroscopy because polyolefins are nonpolar and, therefore, the polymeric matrix is dielectrically invisible [48]. 

Iron catalysts [20-24] have been used to make polyethylene-clay nanocomposites where the polyethylene had very broad molecular weight distribution (MWD). Ziegler-Natta [25, 26], organo-chromium (Phillips) [27], and bis(imino)pyridine iron and cobalt catalysts [28] have also been used to make polyolefin-late transition metal catalysts [29, 30], capable of producing highly branched polyethylene from only ethylene and of promoting the copolymerization of ethylene with polar comonomers, have also been apphed to make polyolefin-clay nanocomposites. 

Compound mixing was performed on different compounding equipment. For EVA organoclay-based nanocomposites, a laboratory twin-roll mill and an internal mixer heated to 145 °C were used. A corotating twin screw extruder from Leistritz, Germany, with a 27-mm screw diameter and an aspect ration of 40 L/D was used to generate polyethylene nanocomposites. The mass temperature was 190 °C at the extruder die. 

In situ polymerization of polyethylene in the presence of montmorillonite is a compelling approach to the preparation of exfoliated polyethylene-montmorillonite nanocomposites. The concern in this approach is similar to the strategy employed in the preparation of nylon 6-montmorillonite nanocomposites by in situ polymerization pioneered by Toyota as found earlier in Chapter 6. The concern about the use of traditional catalysts for the preparation of polyethylene with montmorillonite is in their sensitivity to protons and bases found at the edges of the montmorillonite and the inherent moisture content associated with the coimterions of the montmorillonite. 

Even though this technique has been mostly used with water-soluble polymers, such as PEO, polyvinyl ether (PVE), polyvinylpyrrolidone (PVP), and poly(acrylic acid) (PAA) [134-141], intercalation from nonaqueous solutions has also been reported [142-145]. For example, high-density polyethylene (HDPE)-based nanocomposites have been prepared by dissolving HDPE in a mixture of xylene and benzonitrile with dispersed organomodified layered silicates (OMLSs). The nanocomposite was then recovered by precipitation from tetrahydrofuran (THE) [143], Polystyrene (PS)/OMLS-exfoliated nanocomposites have also been prepared by the solution intercalation technique, by mixing pure PS and organophilic clay with adsorbed cetyl pyrid-ium chloride [146]. Similarly, several studies have focused on the preparation of polylactide (PLA)-layered silicate nanocomposites using intercalation from solution. 

Bocchini S, Frache A, Camino G, Claes M. Polyethylene thermal oxidative stabilisation in carbon nanotubes based nanocomposites. Eur Polym J 2007 43 3222-3235. 

Lee JA, Kontopoulou M, Parent JS. Synthesis and characterization of polyethylene-based ionomer nanocomposites. Polymer 2005 46 5040-5049. 

Rulis AM, Levitt JA (2009) FDA s food ingredient approval process, safety assurance based on sdentilic assessment. Regul Toxicol Pharmacol 53(1) 20-31 Sanchez-Valdes S, Ortega-Ortiz H, Ramos-de Valle LF et al (2009) Mechanical and antimicrobial jHoperties of multilayer films with a polyethylene/silver nanocomposite layer. J Appl Polym Sci lll(2) 953-962... 

The chapter deals with a brief account of various topics in polyethylene-based blends, composites and nanocomposites. We discuss the different topics such as ultra high molecular weight polyethylene (UHMWPE) for orthopaedics devices, stabilization of irradiated polyethylene by the introduction of antioxidants, polyethylene-based conducting polymer blends and composites, polyethylene composites with hgnocellulosic material, LDH as nanofillers of nanocomposite materials based on polyethylene, ultra high molecular weight polyethylene and its reinforcement/oxidative stability with carbon nanotubes in medical devices, montmorillonite polyethylene nanocomposites, and characterization methods for polyethylene based composites and nanocomposites. 

Visakh P. M and Maria lose Martinez Morlanes (eds.) Polyethylene-Based Blends, Composites and Nanocomposites, (1-20) 2015 Scrivener Pubhshing LLC... 

Characterization Methods for Polyethylene-Based Composites and Nanocomposites... 

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