MWNTs polymer-MWNT nanocomposites

Due to their unique mechanical and electronic properties carbon nanotubes (CNT) are promising for use as reinforcing elements in polymer matrixes [1, 2]. The main problems are creation of strong cohesion of CNT with a polymer matrix and uniform distribution of CNT in matrix [3], The goals of this work were development of PTFE-MWNT nanocomposite material with high mechanical characteristics and investigation of influence of MWNT surface groups on mechanical and electronic parameters of the composite material. 

Most of the previous studies on flame retardation of polymer nanocomposites are focused on the relationship between macroscopic morphologies of chars and the flammability properties. Fang et al. studied the relationship between evolution of the microstructure, viscoelasticity and graphitization degree of chars and the flammability of polymers during combustion (68). The flame retar-dancy of ABS/clay /MWNTs nanocomposites was strongly affected by the formation of a network structure. Flammability properties... 

The melting temperatures and crystallization temperatures were measured by the differential scanning calorimetry (DSC) data obtained for the pristine P3HT and P3HT-MWNT nanocomposites and purified MWNTs (Table 12.1). The melting temperatures and crystallization temperatures of the composites also confirm that the composites prepared with low MWNT loading are more thermally stable. The probability of the P3HT interaction with the walls of more thermally stable CNTs is more via the main chain instead of side chains. The probabiUty of this interaction decreases as the MWNT content is further increased in the polymer matrix because now the probabiUty of the wall-wall interaction is more than that of the waU-chain interaction. 

For bulk materials, Jin et al fabricated poly (methylmethacrylate) (PMMA)/MWNT nanocomposites by melt mixing. MWNTs were well dispersed in the matrix [90]. Melt compounding is also widely used for the fabrication of composite fibers. Sandler et al mixed polyamide-12 pellets and CNTs in a twin-screw micro-extruder and then the extrudate was chopped and fed into a capillary rheometer with 1 mm die. The CNTs in the spun fibers were uniformly dispersed [91]. Not only can thermoplastic polymers be melt-compounded, polyimide, a thermoset plastic, can be also prepared by mixing the imide oligomer at 320 °C on a steel plate and then cured at 370°C. It was found that the dispersion of CNTs in... 

MWNT TEM images of MWNT are shown in Figure 10.23. The lower maginification picture in the figure shows that the tubes appear to be flexible and have more of an appearance of noodles than of rods. Many studies have been published on the enhancement of electric conductivity " and of mechanical properties of polymers by polymer-MWNT nanocomposite, and on the flammability of polymer-MWNT nanocomposites. It was also reported that the oxidation of PS, PP, and poly(vinylidene flnoride) is retarded by the addition of carbon nanotubes. ... 

Polymer-multi walled carbon nanotube (MWNT) nanocomposites were first prepared by y-irradiation polymerization of vinyl monomers with funetional groups for application as electron transfer materials in aqueous solution at room temperature and ambient pressure by Yang et al. The vinyl monomers... 

Polymer-MWNT nanocomposites have been obtained by y-irradiation polymerization of various vinyl monomers. Among them, the poly(VPBAc)-MWNT nanocomposite was used as sensing sites in enzyme-free glucose sensors for the detection of glucose without enzymes. The prepared poly(VPBAc)-MWNT nanocomposite electrodes displayed an excellent linear response to glucose concentration in the range 1.0-10 mM. 

Polymer-MWNT nanocomposites in ionic liquids were prepared by the immobilization of 1-butylimidazole bromide on to an epoxy group on a... 

An electrogenerated chemiluminescence (ECL) biosensor based on polymer-MWNT nanocomposites was prepared by y-irradiation polymerization for ethanol sensing. A higher sensing efficiency for ethanol using the ECL biosensor prepared with PAAc-MWCNT nanocomposites was measured compared with that of an ECL biosensor prepared with PMAc-MWCNT nanocomposites and purified MWCNTs. Experimental parameters affecting ethanol detection were also examined in terms of pH and the content of PAAc-MWCNT nanocomposites in Nafion. Little interference from other compounds was observed for the assay of ethanol. The results suggest that this ECL biosensor could be applied for ethanol detection in real samples. 

Radiolytic deposition of Pt-Ru nanoparticles on polymer MWNT nanocomposites was performed by y-irradiation in aqueous solution at room temperature and ambient pressure. The three polymers used were poly(AAc), poly(MAc) and poly(VPBAc). The Pt-Ru nanoparticles were then deposited on to polymer-MWNT nanocomposites by the reduction of metal ions using y-irradiation to obtain polymer-MWNT with Pt-Ru nanoparticles. The catalysts obtained were then characterized by XRD, XPS, TEM and elemental analysis. The catalytic efficiency of the catalyst based on polymer-MWNT nanocomposites was examined for CO stripping and MeOH oxidation for use in a direct methanol fuel cell (DMFQ. The catalyst based on polymer-MWNT nanocomposites shows enhanced activity for the electrooxidation of CO and MeOH oxidation over that of a commercial E-TEK catalyst. 

Pt-M catalysts (M = Ru, Ni, Co, Sn and Au) based on polymer-MWNT nanocomposites were prepared using one-step y-irradiation. Two different types of functional polymers, poly(vinylphenylboronic acid) (PVPBAc) and polyvinylpyrrolidone (PVP), were used to prepare nanocomposites. The Pt-M catalysts obtained based on polymer-MWNT nanocomposites were then characterized by XRD, TEM and elemental analysis. The catalytic efficiency of the Pt-M catalysts based on polymer-MWNT nanocomposites was also examined for CO stripping and MeOH oxidation for use in a DMFC. The catalytic efficiency of the Pt-M catalyst based on polymer-MWNT nanocomposites for MeOH oxidation followed the order Pt-Sn > Pt-Co > Pt-Ru >Pt-Au>Pt-Ni catalysts. The CO adsorption capacity of the Pt-M catalyst based on polymer-MWNT nanocomposites for CO stripping decreased in the order Pt-Ru > Pt-Sn > Pt-Au > Pt-Co > Pt-Ni catalysts. 

Poly(vinyl alcohol) (PVA) substrates coated with a non-porous hydrophilic polymer/multiwalled nanotube (MWNT) nanocomposite layer have been put forward for potential use in oil/water emulsion separation (Wang et al, 2005). Specifically, it has been proposed that CNTs could improve the flux rate for the formation of hydrophilic nanochannels for water transfer through nanocomposite membranes. The immobilization of CNTs in hydrophobic membrane pores was shown to have a favourable effect on water-membrane interactions and to promote higher vapour permeability, since liquid was prevented from entering the membrane pores (Gethard et al, 2011). The literature also mentions improvements in water flux and selectivity when polymeric membranes are loaded with hydrophilic nanofiUers, including silica (Bottino et al, 2001), ZrOj (Bottino et al, 2002) and HO2 (Yang et al, 2006). 

CNTs can enhance the thermal properties of CNT-polymer nanocomposites. The reinforcing function is closely associated with the amount and alignment of CNTs in the composites. Well-dispersed and long-term stable carbon nanotubes/ polymer composites own higher modulus and better thermal property as well as better electronic conductivity (Valter et al., 2002 Biercuk et al., 2002). Both SWNT and MWNT can improve the thermal stability and thermal conductivity of polymer, the polymer-CNT composites can be used for fabricating resistant-heat materials. 

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