Polyethylene oxide nanocomposites

A detailed II NMR kinetic investigation132 of the polymerization of aniline in DC1/D20 solution has revealed no significant differences between the rates of dispersion polymerization using a polyethylene oxide)-based stabilizer and standard precipitation polymerization in the absence of any stabilizer. However, faster polymerization of aniline was observed in the presence of 20 nm silica particles, leading to PAn-silica nanocomposites. In contrast, slower polymerization occurred in the presence of surfactant micelles to form surfactant-stabilized PAn particles, presumably owing to the high solution viscosity. 

Electrospinning processes are used to prepare nanocomposite fiber mats. In order to prepare nanocomposite fiber mats, mixtures containing the polymer solution and cellulose whiskers solution are placed in the appropriated electrospinning setup. Peresin et al. [128] have produced nanocomposite mats of poly (vinyl alcohol) (PVA) reinforced with cellulose nanocrystals using this electrospinning technique. Smooth nonwoven mats with homogeneous nanofibers were obtained. Park et al. [129] have also incorporated cellulose whiskers into nanofibers of polyethylene oxide (PEO) by the electrospiiming process. 

H. Qin, C. Zhao, S. Zhang, G. Chen, M. Yanga, Photo-oxidative degradation of polyethylene/montmOTillonite nanocomposite. Polym. Degrad. Stab. 81, 497-500 (2003)... 

Recently, Moad et al. [288,289] designed and prepared novel copolymer intercalant/dis-persant/exfoliant systems that are effective with unmodified clays at low levels (<20% with respect to clay), can be combined with commercial PP and clay in a conventional melt-mixing process, and do not require the use of additional compatibilizers. PP-clay nanocomposites prepared by direct melt mixing using unmodified MMX clays and a copolymer additive added at a level of only 1 wt.% with respect to PP for 5wt.% clay Authors investigated the following two classes of dispersants (1) polyethylene oxide-based nonionic surfactants... 

Dintcheva, N. Tz., Al-Malaika, S., and La Mantia, F. P. 2009. Effect of extrusion and photo-oxidation on polyethylene/clay nanocomposites. Polymer Degradation and Stability 94 1571-1588. 

Recent publications describe the effects of silica on the conductivity and mechanical properties of a polyethylene oxide/ammonium bifluoride complex containing propylene carbonate [36], as a foam stabilizer in polyester polyurethane foams, and on the properties of polylactic acid nanocomposites prepared by the sol-gel technique [37] (see also Chapter 24), on the mechanical properties and permeability of i-PP composites [38], on the surface hardness of polymers for biomedical devices [39], on enhanced properties of polymer interlayers that are used in multiple layer glazing panels [40]. 

Electrical conductivity measurements have been reported on a wide range of polymers including carbon nanofibre reinforced HOPE [52], carbon black filled LDPE-ethylene methyl acrylate composites [28], carbon black filled HDPE [53], carbon black reinforced PP [27], talc filled PP [54], copper particle modified epoxy resins [55], epoxy and epoxy-haematite nanorod composites [56], polyvinyl pyrrolidone (PVP) and polyvinyl alcohol (PVA) blends [57], polyacrylonitrile based carbon fibre/PC composites [58], PC/MnCli composite films [59], titanocene polyester derivatives of terephthalic acid [60], lithium trifluoromethane sulfonamide doped PS-block-polyethylene oxide (PEO) copolymers [61], boron containing PVA derived ceramic organic semiconductors [62], sodium lanthanum tetrafluoride complexed with PEO [63], PC, acrylonitrile butadiene [64], blends of polyethylene dioxythiophene/ polystyrene sulfonate, PVC and PEO [65], EVA copolymer/carbon fibre conductive composites [66], carbon nanofibre modified thermotropic liquid crystalline polymers [67], PPY [68], PPY/PP/montmorillonite composites [69], carbon fibre reinforced PDMS-PPY composites [29], PANI [70], epoxy resin/PANI dodecylbenzene sulfonic acid blends [71], PANI/PA 6,6 composites [72], carbon fibre EVA composites [66], HDPE carbon fibre nanocomposites [52] and PPS [73]. 

Silicate clays as recovered from nature do not lead to the formation of nanocomposites by simply physically mixing them with a polymer. Except with few hydrophilic polymers like polyethylene oxide [49-52] or polyvinyl alcohol [53,54], which have good interaction with the inorganic, highly hydrophilic, layered silicates, the surfaces of the silicates have... 

Tjong et al. [16] showed that the dielectric constant of nanocomposites of annealed low-density polyethylene and zinc oxide was higher than that of quenched nanocomposites, whereas the resistivity of annealed low-density polyethylene-zinc oxide nanocomposites was considerably lower than that of the quenched samples. The dielectric constant of both the annealed and quenched low-density polyvinyl-zinc oxide nanocomposites showed a pronounced frequency dependence when the zinc oxide volume content reached 52 vol% as a result of the formation of the zinc oxide network. 

In situ polymerisation of the polymer matrix is an attractive method of preparing graphene-based composites although often solvents are used to reduce the viscosity of the dispersions. For example, intercalative polymerisation of methyl methacrylate and epoxy resins has been achieved with graphene oxide to produce nanocomposites with enhanced properties. It has also been possible to use in situ polymerization produce polyethylene- and polypropylene-matrix graphene oxide nanocomposites. The technique of grafting poly(methyl methacrylate) chains onto graphene oxide has also been employed to make the filler compatible with the polymer matrix. " ... 

Dintcheva, N.T., Al-Malaika, S., La Mantia, F.P. Photo-oxidation of polyethylene/clay nanocomposites. Polym. Degrad. Stab. 94, 1571-1588 (2009)... 

Chen-Yang, Y.W., Wang, Y, Chen, Y, Li, Y, Chen, H., and Chiu, H. (2008) Influence of silica aerogel on the properties of polyethylene oxide-based nanocomposite polymer electrolytes for lithium battery, J. Power Sourc., 182, 340-348. 

Iron oxide nanocomposites have been prepared by hydrolysis of iron salts in sulfonated polystyrene resins, mesoporous sulfonated styrene-divinylbenzene copolymer, acrylonitrile-methyl methaciylate-divinylbenzene copolymer, cross-linked high amylose starch, polyimides, polyvinylpyridine, polypyrrole,eellulosies. Nanocomposites of metals (Cr, Mo, W, Fe, Co, Ni) with a variable particle size (2-10 mn), have been prepared from solutions of metal preeursors in a molten polymer (polyethylene, polypropylene, polytetra-fluoroethylene, polyamide, polyaiylate, polycarbonate, polystyrene, polyethers, polyphenyleneoxide, siloxane). There are also many examples of in-situ precipitation of iron oxides in aqueous solution of polymers, such as dextran, PVA, polyethylene glycol, etc. In this case, size dispersion and aggregation are frequent, but they can be minimized by using reverse micelles. ... 

Thermal and Thermal-oxidative Degradation of Polyethylene Nanocomposite Prepared by Intercalation Polymerization... 

Keywords Catalysis intercalation polymerization kinetics layered clay nanocomposite oxidation polyethylene thermal degradation... 

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