Nano-ZnO

ZnO nanoparticles possess greater surface/volume ratio. When used in carboxylated nitrile rubber as curative, ZnO nanoparticles show excellent mechanical and dynamic mechanical properties [41]. The ultimate tensile strength increases from 6.8 MPa in ordinary rabber grade ZnO-carboxylated nitrile rubber system to 14.9 MPa in nanosized ZnO-carboxylated nitrile mbber without sacrificing the elongation at failure values. Table 4.1 compares these mechanical properties of ordinary and nano-ZnO-carboxylated nitrile rubbers, where the latter system is superior due to more rubber-ZnO interaction at the nanolevel. 

Different polymer-nano-ZnO hybrid systems based on epoxyl2 [42], poly(styrene-co-acrylic acid) [43], polyurethane [44], etc. have been reported by several other researchers. 

Comparative Mechanical Properties Data on Ordinary ZnO and Nano-ZnO-Filled Carboxylated Nitrile Rubber Systems... 

FIGURE 4.8 Comparative tensile stress-strain plot of polychloroprene-ordinary zinc oxide (ZnO) and poly-chloroprene-nano-ZnO system. (From Sahoo, S., Kar, S., Ganguly, A., Maiti, M., and Bhowmick, A.K., Polym. Polym. Compos., 2007 (in press). Courtesy of Smithers Rapra Technology Ltd.)... 

Mueler et al. and Gottschalk et al. [43, 44] presented a model for predicting concentrations of nanoparticles including nano-Ag, nano-Ti02, nano-ZnO, fullerenes, and carbon nanotubes (CNT) in different environmental compartments. The results of this study demonstrated that modeling is a meaningful utility to carry out quantitative risk assessment of nanoparticles. 

Nano-Ti02, nano-ZnO, Air, surface water, STP effluent, U.S., Europe and nano-Ag, carbon and sewage sludge, soil, Switzerland... 

The study [56] included calculations of PECs for nano-Ti02, nano-ZnO, nano-Ag, CNTs, and fullerenes for the USA, Europe, and Switzerland. In the first work [60], simulations were run to recalculate PECs for nano-Ti02, nano-Ag, and CNTs in Switzerland which were contrasted to the corresponding results of the initial and comparative modeling of Mueller and Nowack [8]. Basically, these simulations confirmed the nanomaterial flow modeling presented by Mueller and Nowack... 

Figure 2. The mechanism for preparation of Nano ZnO-CHIT electrode and immobilization of ChOx onto NanoZnO-CHIT Nanocomposite, Reprinted from Analytica Chimica Acta, 616, R. Khan, A. Kaushik, P. R. Solanki, A.A. Ansari, M.K. Pandy, B.D. Malhotra, Zinc oxide nanoparticles -chitosan composite film for cholesterol biosensor, 209,Copyright( 2008) with permission fom Elsevier.

Chitosan has been utilized along with hydrothermally prepared nano-ZnO nanoparticles for DNA hybridization detection. The detection limit is obtained as 1.09 x 10"11 mol L 1 of complementary target [66], A MWNTs/nanoZnO/CH modified nanocomposite GCE electrode has been used for DNA immobilization via physisorption. This biosensor can effectively discriminate different DNA sequences related to PAT gene in the transgenic com, with detection limit of 2.8 x K)"12 mol/L of target sequence [67], In another report they have deposited ZnO nanoparticles, MWNTs and CH layer onto glassy carbon electrode to immobilize ssDNA probe. A remarkable synergistic effect of the ZnO nanoparticles and MWNTs has been achieved after ssDNA probe immobilization for fabrication of sensitive electrochemical DNA biosensor. The modified electrode shows a wide linear response for DNA hybridization detection. (1.0 x 10"11 to 1.0 x 10"6 mol/L) with detection limit of 2.8 x 1 O 12 mol/L [68],... 

Dutta S, Chattopadhyay S, Jana D, Banerjee A, Manic S, Pradhan S K, Sutradhar M, SarkarA, Annealing effect on nano ZnO powder studied from positron life time and optical absorption spectroscopy, J. Appl. Phys., 100, 114328-6, 2006. 

Chinese vinegars [81] Identification of several commercial vinegars 9 doped nano-ZnO thick film sensors... 

In the case of PPS nano-ZnO composites, the crystallization time becomes shorter than that of neat PPS at the same crystallization temperature. PPS/nano-ZnO composites may exhibit a heterogeneous nucle-afion in a wide range of crystallization temperatures in contrast to neat PPS [79]. 

Nano ZnO-catalyzed one-pot Knoevenagel condensation of cyclohexane-1,3-diones with various fl-formyl esters followed by lactonization give access to tetrahydrocoumarins (14TL2908). 

S. K. Dhoke and A. S. Khanna, Effect of nano-ZnO particles on the corrosion behaviour of alkyd-based waterborne coatings , Prog Org Coat, 2009,64,371-82. 

The inclusion of nano-ZnO into polymers can enhance both the mechanical and optical properties of the polymers due to strong inter facial... 

Also, nanomodified ZnO is found to improve photocatalytic properties compared to micro-sized ZnO. Sebastian et al showed that the intensity of blue colour of methylene blue dye reduced at a faster rate in presence of nano-ZnO due to the enhanced rate of photo decomposition of the dye. 

With a view to modify the hydrophilic surface of ZnO to hydrophobic surface so as to improve the dispersion of the particles in the nonpolar polymer like NR matrix and also to reduce the agglomeration of the nanoparticles of ZnO, Taghvaei-Ganjeli et al. modified the surface of nano-ZnO by treating its aqueous suspension with PEG and PPG as discussed in Section 12.5.2. He... 

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