Montmorillonite Polyethylene Nanocomposites

Stoeffler et al. [70] also tried imidazolitun and phosphonium salts together to pyridinium salts as surfactants for Mt to obtain PE nanocomposites. Most of authors modified the Mt with the amount of salt required to intercalate 100% of the CEC of the Mt. Mandalia and Bergaya [71] studied the effect of surfactant/CEC ratio, obtaining that the amount of surfactant had a direct effect on the interlayer separation of the clay, and with clay mineral having a high surfactant load (150 to 200% of CEC) the polymer intercalation was more homogeneous. 

Sanchez-Valdes etal. [68] prepared the OMt LLDPE-g-MA CPN by melt blending in a twin screw extruder using two steps mixing and one step mixing. Most of authors describe no effect of the Mt on the thermal stability of PE composites and nanocomposites, but there are others who describe an increase or decrease in the stability. Anyhow, the described shifts in the thermal decomposition temperature are small and may depend on different 

8 Characterization Methods for Polyethylene-Based Composites and Nanocomposites 

By extrusion of PE composites, PE granules or powder with fiber/filler are fed from the hopper to the screw and are then pushed along the barrel 

Schmitt, TEM analysis of microstructural morphology in ultra high molecular weight polyethylene . Scripta Materialia 43, 523-528 (2000). 

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T. H. Chuang, W. Guo, K. C. Cheng, S. W. Chen, H. T. Wang, and Y. Y. Yen, Thermal properties and flammability of ethylene-vinyl acetate copolymer/montmorillonite/ polyethylene nanocomposites with flame retardants. Journal of Materials Research, 11 (2004), 169-74. 

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. 

Chapter 8 explains the main aspects of montmorillonite polyethylene nanocomposites, focusing on the processing, properties and applications and the compoxmding and characterisation techniques to manufacture PE/ Mt nanocomposites. Some of the topics addressed include the characterisation of Mt, morphology of PE/Mt nanocomposites and the influence in mechanical, thermal and other properties. Future work regarding PE/Mt nanocomposites is also included. 

This chapter covers fundamental and applied research on polyester/clay nanocomposites (Section 31.2), which includes polyethylene terephthalate (PET), blends of PET and poly(ethylene 2,6-naphthalene dicarboxy-late) (PEN), and unsaturated polyester resins. Section 31.3 deals with polyethylene (PE) and polypropylene (PP)-montmorillonite (MMT) nanocomposites, including blends of low density polyethylene (LDPE), linear low density polyethylene (LLDPE), and high density polyethylene (HDPE). Section 31.4 analyzes the fire-retardant properties of nanocomposites made of high impact polystyrene (HIPS), layered clays, and nonhalogenated additives. Section 31.5 discusses the conductive properties of blends of PET/PMMA (poly (methyl methacrylate)) and PET/HDPE combined with several types of carbon... 

TEM micrograph (scale bar 100 nm) for a polyethylene nanocomposite containing acid-treated montmorillonite (5.4 wt%). The material was made by in situ polymerization using Zr(CH2Ph)4 supported on the Al Bug-treated clay, using a prepolymerization step. 

The impact on the PHRR when substituting a polymer oligomer as a surface treatment on montmorillonite for a quaternary ammonium ion is not a panacea [51,52]. The comparison of methylmethacrylate oligomer-treated montmorillonite with quat-treated montmorillonite in poly(methylmethacrylate), polystyrene, high-impact polystyrene, acrylonitrile-butadiene-styrene terpolymer, polypropylene, and polyethylene nanocomposites indicated sensitivity to polymer type and a poor correlation to the degree of exfoliation determined by X-ray analysis and TEM. The impact of polymer structure associated with the montmorillonite appears to be a significant variable relating to the PHRR of these composites. In this book, chapter 4 on barriers... 

Kumanayaka, T.O., Parthsarathy, R., Jollands, M. Accelerating effect of montmorillonite on oxidative degradation of polyethylene nanocomposites. Polym. Degrad. Stab. 95, 672-676 (2010)... 

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. 

Intercalation of organic molecules into layered host lattice produces a variety of organic-inorganic hybrid materials. The solvothermal method provides a reaction system that allows application of high temperatures and therefore is a powerful technique for preparation of intercalation compounds. Exfoliation of layers may occur because of applied high temperatures. For example, exfoliated poly-ethylene/montmoriUonite nanocomposites were reported to be prepared by solvothermal reaction of organophilic montmorillonite with polyethylene in toluene at 170°C for 2... 

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. 

The processes of the combustion are studied for the number of a polymeric nanocomposites based on the layered silicates such as ttylon-6.6 with 5 wt% of Cloisite 15A - montmorillonite being modified with the dimethyldialkylammonium (alkyls studied CIS, C16, C14), maleinated polypropylene and polyethylene, both (1.5%) with 10 wt% Cloisite 15 A. The general trend is two times reduction of the speed of the heat release. The decrease in the period of the flame induction is repotted for all nanocomposites in comparison with the initial polymers [54]. 

Jin, Y.-H., Park, H.-J., Im, S.-S., Kwak, S.-Y, and Kwak, S. 2002. Polyethylene/clay nanocomposite by in situ exfoliation of montmorillonite during Ziegler-Natta polymerization of ethylene. Macromolecular Rapid Communications 23 135-140. 

Liang, G., Xu, J., Bao, S., and Xu, W. 2004. Polyethylene/maleic anhydride grafted polyethylene/ organic-montmorillonite nanocomposites. I. Preparation, microstructure, and mechanical properties. Journal of Applied Polymer Science 91 3974—3980. 

Liao, B., Liang, H., and Pang, Y. 2001. Polymer-layered silicate nanocomposites. 1. A study of poly (ethylene oxide)/Na+—montmorillonite nanocomposites as polyelectrolytes and polyethylene-block-poly(ethylene glycol) copolymer/Na+— montmorillonite nanocomposites as fillers for reinforcement of polyethylene. Polymer 42 10007-10011. 

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