Filler hybrid

At fixed filling ratio, using a hybrid filler may decrease extruded material swelling, raise the critical deformation parameters at which elastic turbulence of the melt may begin [366]. 

Among other fillers of note are aluminium flakes [15], hybrid fillers — a mixture of flakes and fibers (Transmet Corp.) [14], mica coated with a layer of Ni (Martin Marietta) [14], etc. 

FIGURE 12.25 Cycle performance of cathodes having different amount of carbon black and hybrid fillers. (Adapted from Sotowa, C., et al., Carbon, 1, 911, 2008.)... 

Figure 4.11. Schematic illustration showing the procedure for growth of carbon nanotubes on clay platelets and incorporation of CNT-clay hybrid filler into PA6 matrix for making the PA6/CNT-clay composite. Reprinted with permission from ref (55).

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

So far, utilization of as-prepared clay-CNTs hybrid in polymer composites exhibits good properties, especially mechanical properties. However, the versatile structure of this hybrid synthesized by different processing conditions lead to different composites properties. So the effect of fabrication method and process parameters on final properties of polymer composites should be investigated more systematically. For example, the density and length (or diameter) of CNTs on clay platelets may affect the properties of hybrid. It is interesting to enhance the connection between clay and CNTs in order to obtain higher mechanical properties for the hybrid filler and composites. 

A method of incorporating simultaneously hybrid fillers of CB and MWNTs into a polymeric matrix has also been used to enhance the electrical conductivity of composites because the CB particles link the gaps between the unconnected MWNTs thus improving the formation of connected structures (51,52). In fact the synergistic effects arising between the two different fillers improve the dispersion of MWNTs in the polymer matrix. 

R. De Santis, A. Gloria, T. Russo, U. D Amora, V. D Anto, F. Bollino, L. Ambrosio, et al.. Advanced composites for hard-tissue engineering based on PCL/organic-inorganic hybrid fillers from the design of 2D substrates to 3D rapid prototyped scaffolds. Polymer Compos. 34 (2013) 1413-1417, doi 10.1002/pc.22446. 

This PANl-MWCNT hybrid filler was solution blended with PS matrix (10-30 wt.% loading) resulting in absorption dominated total shielding effectiveness (SE.j.) of -45.7 dB (Figure 9.21a) in the 12.4-18.0 GHz range and at a sample thickness of 2.0 mm. The enhanced SE.j. was ascribed to optimization of electrical conductivity, skin depth, complex permittivity... 

Materials selection windows of the hybrid fillers for the desired flexural strength and electrical conductivity... 

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. 

CB is often used together with other fillers to get hybrid fillers, and the NR composites reinforced with hybrid fillers will be discussed in the next section. 

NR composites with excellent properties. A few efforts have been devoted to preparing NR nanoeomposites using two or even more different kinds of fillers. The synergistie effeet of hybrid fillers ean be used to design high-performance NR nanoeomposites. 

Jong et prepared NR composites reinforced with hybrid filler consisting of defatted soy flour (DSF) and CB. Aqueous dispersions of DSF and CB were first mixed, and then blended with NR latex and sulfur dispersion, respectively. The homogenous composite mixtures were quickly freeze-dried and compression moulded to offer the NR composites. They found that the NR composites reinforced with 40% of hybrid filler (the ratio of DSF to CB was 1 1) exhibited a 90-fold improvement in the rubber plateau modulus compared with unfilled NR, showing a significant reinforcement effect by the hybrid filler. 

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. 

Natural Rubber with Hybrid Filler System (Carbon Black and Clay)... 

Figure 8.21 Filler-filler network (Payne effect) in hybrid filler filled NR composites.

Effects of Hybrid Fillers on Mechanical Properties of Natural Rubber Composites... 

Recently, a method of incorporating combination different types of fillers simultaneously into the rubber matrix has been put forward. The hybrid filler composites were developed in manufacturing industry for various reasons including to meet specific processing and performance requirements which cannot be satisfied using single component, scientific interests to develop new materials with a unique material property characteristic and financial or economic advantages. ... 

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