Hybrid filler nanocomposites

Furthermore, CNT-clay hybrid filler can also be used to prepare polymer nanocomposites by solution based method. Hydrophilic... 

FIGURE 5.93 Schematic presentation of the procedure of growing carbon nanotubes (CNT) on clay particles and incorporation of CNT-clay hybrid filler into PA6 matrix for making PA6/CNT-clay nanocomposite. (After Zhang, W. D., Phang, I. Y., and Liu, T. 2006. Adv. Mater., 18, 73. With permission.)... 

Aramid nanocomposite films with 1% hybrid fillers of graphene and multi-walled carbon nanotubes have been prepared by solution casting [28]. The electric heating behavior has been investigated as a function of the composition of the carbon fillers. The electrical resistivity can be controlled by the amount of graphene and carbon nanotubes added. 

Jeon GW, Jeong YG. Electric heating films based on m-aramid nanocomposites containing hybrid fillers of graphene and carbon nanotube. J Mater Sci 2013 48(ll) 4041-9. 

CB is often used together with other fillers to get obtain hybrid fillers to further enhance NR properties. Liu et al. added nanosized CB and poly(ethylene glycol) (PEG) modified clay to prepare NR nanocomposites. They suggest that NR with hybrid fillers exhibits superior mechanical properties compared to NR with CB as the sole filler. Rattanasom et al also reported that the tensile strength and elongation at break increase from 15.3 to 25.4 MPa and 460 to 605%, respectively, for the CB-filled NR as compared to NR with hybrid fillers (CB and modified clay). 

A synergistic effect was also found between clay and CB N330 from Cabot, in NR based nanocomposites prepared by emulsion compounding.It was observed that both fillers were dispersed at nanoscale and randomly in the NR matrix the space between the clay layers was filled with CB particles. The mechanical properties of the nanocomposites, such as moduli at 100% and 300% elongation, tensile strength and tear strength were much improved, at the same total filler level, by the hybrid filler system, with respect to composites containing only one filler. 

NR composites and nanocomposites can be fabricated by three main techniques, namely latex compounding, solution mixing and melt blending. A variety of nanofillers, such as carbon black, silica, carbon nanotubes, graphene, calcium carbonate, organomodified clay, reclaimed rubber powder, recycled poly(ethylene terephthalate) powder, cellulose whiskers, starch nanocrystals, etc. have been used to reinforce NR composites and nanocomposites over the past two decades. In this chapter, we discuss the preparation and properties of NR composites and nanocomposites from the viewpoint of nanofillers. We divide nanofillers into four different types conventional fillers, natural fillers, metal or compound fillers and hybrid fillers, and the following discussion is based on this classification. 

Another promising approach to preparation of novel NR composites and nanocomposites with excellent properties is to adopt hybrid fillers because each reinforcing agent can retain its inherent advantages, which imparts a synergistic effect between hybrid fillers to reinforce NR nanocomposites. 

A large-scale application of rubber nanocomposites, such as the one in the tyre industry, reasonably implies the use of hybrid filler systems, with a minor amount of nanofiller added to a major part of a traditional filler, such as silica or carbon black. 

Addition of small amount of nanofillers may improve the properties of mbber and thermoplastics. In the polymer industry, polymer-filler nanocomposites are a promising class of material that offers the possibility of developing new hybrid materials with desired set of properties. Properties of mbbers and thermoplastics which have shown substantial improvements due to the incorporation of nanoparticles, are mechanical properties, decreased permeability to gases, water and hydrocarbons, thermal stability and heat distortion temperature, flame retardancy and reduced smoke emissions, chemical resistance, surface appearance, electrical and thermal conductivity, optical clarity in comparison to conventionally filled polymers [107]. 

Ma PC, Liu MY, Kim JK, Tang BZ, et al. Enhanced electrical conductivity of nanocomposites containing hybrid fillers of carbon nanotubes and carbon black. ACS Appl Mater Interfaces May 2009 l(5) 1090-6. 

Effect of Hybrid Fillers on the Non-Linear Viscoelasticity of Rubber Composites and Nanocomposites... 

Polymer/mbber nanocomposites exhibit enhanced mechanical, thermal stability, toughness, stiffness, and gas-barrier properties compared to those of conventional composites at same filler volume fraction [11-15]. The interaction between the filler and polymer matrix of nanocomposites at the nanometer scale enables the formation of molecular bridges in the polymer matrix. This is the basis for the enhanced mechanical properties of nanocomposite as compared to conventional microcomposites [16, 17]. Nanocomposites containing hybrid fillers add a new dimension to the above enhanced properties. These composites show more advantages to composites containing single filler as the property of the hybrid filler composite depends upon the combined effect of individual filler. The nonlinear viscoelastic behavior of nanocomposites can be influenced differently by hybrid fillers than single filler. 

This chapter focuses on the non-linear viscoelastic behavior of rubber composites and nanocomposites. Here, we have discussed about the effect of individual fillers (mineral fillers, nanotubes, carbon nanofillers, fibrous nanofiUers, biofillers, special structured fillers viz. nanorods, nanowires, nanoflowers etc.) on the linear/ nonlinear viscoelastic behavior of rubber composites. Moreover, as this chapter is more concerned on the non-linear viscoelastic behavior, we have also discussed the effect of hybrid fillers on the nonUnear viscoelastic behavior of rubber composites in more detail. 

Hybrid fillers for rubber composites/nanocomposites are getting importance because they offer a range of properties that cannot be obtained with a single type of reinforcement. Hybrid composites have attracted the attention of many researchers as a way to enhance the mechanical properties [19, 35]. Hybrid... 

The viscoelastic properties of natural rubber (NR) nanocomposites filled with silica/multiwall carbon nanotube hybrid fillers have been studied by H. Ismail et al. [46]. The addition of hybrid fillers (MWCNTs-i-silica) to the NR matrix... 

Ismail H, Ramly AF, Othman N (2013) Effects of silica/multiwall carbon nanotube hybrid fillers on the properties of natural rubber nanocomposites. J Appl Polym Sci 2433... 

Madaleno, L., R. Pyrz, L. R. Jensen, J. J. C. Pinto, A. B. Lopes, V. Dolomanova, and J. Schjpdt-Thomsen. 2012a. Synthesis and characterization of montmoiiUonite-carbon nanotnhes hybrid fillers for nanocomposites. Polym. Polym. Comp. 20 693-700. 

The development of hybrid materials such as CNT/inorganic hybrids has drawn great interest for its combination of multiphase characteristics of nanocomposites with the synergistic function of each hybrid constituent. Utilization of the hybrid filler is one of the ways to improve the properties of composites. Some work has demonstrated hybrid systems made of CNTs with inorganic fillers such as mica, silica (Si02), magnesia (MgO), and calcium carbonate (CaCOs). All of these inorganic materials have been extensively employed as fillers in composites, because of several remarkable benefits such as abundant raw-material resources and stable properties. 

In Part Two, Chapter 4 describes a general fabrication-characterization route of electrospinning PLA poly(s-caprolactone) (PCL)/HNT composite fibers. The effects of HNTs with or without the modifier 3-aminopropyltriethoxysilane on fiber diameter, morphological structure, thermal properties, crystalline stmctures, and degree of crys-talhnity, as well as the intermolecular interaction of electrospun nanocomposite fibers, are thoroughly studied to provide the appropriate guidance to the controlled drug release associated with fibrous structures. Chapter 5 deals with the synthesis and characterization of CNT hybrid fillers via chemical vapor deposition (CVD) technique for polymer nanocomposites. Optimized synthesis parameters are presented and comparative studies are also conducted between chemical hybrid-filled and physical hybrid-fiUed polymer nanocomposites in terms of their typical applications. 

K. Yang and M. Gu, "Enhanced thermal conductivity of epoxy nanocomposites filled with hybrid filler system of triethylenetetramine-functionalized multi-walled carbon nanotube/silane-modified nano-sized silicon carbide," Composites Part A, vol. 41, pp. 215-221,2010. 

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