Halloysite nanotubes

Fig. 14.13 Schematic illustration of the urease-catalyzed synthesis of CaC03 inside halloysite nanotubes.

Figure 22.4 Scanning electron microscopy image of halloysite nanotubes deposited onto an aluminum alloy surface.

The pH sensitivity of halloysite can be enhanced by using retardant polymers, a cationic coating for the formation of a pH-sensitive polyelectrolyte shell on the nanotubes after their saturation with corrosion inhibitor. To equip the halloysite nanotubes with controlled release properties, the surface of the nanotubes was first loaded with benzotriazole and subsequently modified by LbL deposition of two polyelectrolyte bilayers, thus blocking the tubes openings with polyelectrolytes. 

Du et al. (50) reported the synthesis of butadiene styrene rubber nanocomposites with halloysite nanotubes. The tensile properties of the composites containing various amounts of nanotubes are depicted in Table 2.2. The tensile properties were observed to significantly increase as a function of increasing amount of nanotubes in the composites. For the maximum loading of the nanotubes, a tensile modulus of 5.56 MPa was observed as compared to 1.52 MPa for the pure polymer. 

Table 2.2. Mechanical properties of butadiene styrene rubber nanocomposites with halloysite nanotubes...

Pooria Pasbakhsh, PhD, is currently a Lecturer at the School of Engineering, Monash University Sunway Campus, Malaysia. Dr. Pasbakhsk s research has been centered on the development and application of computational approaches and experimental tools for modern polymers, halloysite nanotubes, and polymer clay nanocomposites. 

Yan, L. Jiang, J. Zhang, Y. Liu, J. Preparation and characterization of large-size halloysite nanotubes particles by a combined technique of interfacial polymerization and condensation polymerization. Journal of Nanoparticle Research (2011), 13(12), 6555-6561. 

Qi, R. Guo, R. Shen, M. Cao, X. Zhang, L. Xu, J. Electrospun poly (lactic-co-glycolic acid)/halloysite nanotube composite nanofibers for drug encapsulation and sustained release. J. Mater. Chem. 2010, 20 (47), 10622-10629. 

Zhao, Y Wang, S. Guo, Q. Shen, M. Shi, X. Hemocompatibility of electrospnn halloysite nanotube and carbon nanotnbe-doped composite poly (lactic-co-glycolic acid) nanofibers. J. Appl. Polym. Sci. 2012,127 (1-4), 4825-4832. 

Successful pilot-scale demonstration of halloysite nanotubes in polypropylene, press release (2/22/07). NatualNano Inc. 2007. 

AUi Alhuthali, A., Low, I. M. Water absorption, mechanical, and thermal properties of halloysite nanotube reinforced vinyl-ester nanocomposites. J. Mater. Sci. 48 (2013) 4260-4273. 

Well-defined coaxial tubular halloysite nanotubes (HNTs)/PPy nanocomposites were synthesized for use as electrode materials for supercapacitors by the in situ chemical oxidative polymerization method based on self-assembled monolayer amine-functionalized HNTs [72]. It showed their greatest conductivity (40 S/cm) at room temperature and a weak temperature dependence of the conductivity from 298 K to 423K. A maximum discharge capacity of 522 F/g after correcting for the weight percent of the PPy phase at a current density of 5 mA/cm in a 0.50 mol/L Na SO electrolyte solution could be achieved in a half-cell setup configuration for the HNTs/PPy composites electrode. 

W.L. Zhang, H.J. Choi, Fabrication of semiconducting polyanihne-wrapped halloysite nanotube composite and its electrorheology. Colloid Polym. Sci., 2012, 290, 1743. 

Hb polymer brushes can be conveniently prepared by surface-initiated ATRP-SCVP of a suitable inimer from an initiator-functionalized surface. Mori et al. describe the synthesis of hb poly(2-(2-bromopropionyloxy)ethyl acrylate and 2-(2-bromoisobutyryloxy)ethyl methacrylate. " Another approach is presented by different groups employing halloysite nanotubes and GMS or 2-(bromoacetyloxy)ethyl... 

Pasbakhsh, R, Ismail, FI., Ahmad Fauzi, M. N., and Abu Bakar, A. 2009. Influence of maleic anhydride grafted ethylene propylene diene monomer (MAH-g-EPDM) on the properties of EPDM nanocomposites reinforced by halloysite nanotubes. Polymer Testing 28 548-559. 

Lau, K.T., and Takagi, H. (2013) Multi-response analysis in the material characterisation of electrospun poly(lactic acid)/halloysite nanotube composite fibres based on Taguchi design of experiments fibre diameter, non-intercalation and nucleation effects. Appl Phys. A Mater. Sci. Process., 112, 747 -757. 

H. J. (2012) Statistical design of experiments for electrospun poly(lactic acid) (PLA)/halloysite nanotube (HNX) composites in response to fibre diameter and... 

Haroosh, H., Chaudhary, D, Dong, Y, and Hawkins, B (2011) Electrospun PLA PCL/halloysite nanotube nanocomposites fibers for drug delivery. Proceedings... 

D., Ingram, G., and Yusa, S. (2013) Electrospun PLA PCL composites embedded with unmodified and 3-aminopropyltriethoxysilane (ASP) modified halloysite nanotubes (HNT). Appl. Phys. A Mater.. Sci. Process., 110, 433-442. 

Figure 19.7 Schematic chemical reaction between halloysite nanotubes and natural rubber with bis(triethoxysilylpropyl)-tetrasulfide (Si-69) coupling agent. (Reprinted from ref. 53 with permission from Elsevier .)...

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