Hybrid filler thermal conductivity

For the N22 CMC system, remaining open porosity in the CVI SiC matrix was filled by room-temperature infiltration of SiC particulate or slurry casting, followed by the melt-infiltration (MI) of silicon metal near 1400°C. This yielded a final composite with 2% closed porosity within the fiber tows and 0% porosity between the tows. The final composite system (often referred to as a slurry-cast MI composite) typically displayed a thermal conductivity about double that of a full CVI SiC composite system in which the CVI matrix process was carried to completion. Also the composite did not require an oxidation-protective over-coating to seal open porosity. Decreasing the porosity of the hybrid matrix also increased the N22 CMC elastic modulus, which in turn contributed to a high proportional limit stress. However, since the filler contained some low-modulus silicon, the modulus increase was not as great as if the filler were completely dense SiC. 

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]. 

Zhou T, Wang X, Liu X and Xiong D (2010), Improved thermal conductivity of epoxy composites using a hybrid multi-walled carbon nanotube/micro-SiC filler . Carbon, 48, 1171-1176. doi 10.1016/j.carbon.2009.11.040. 

Polymers can be filled with hybrid particles or with a combination of fillers in order to better control their thermophysical behavior (Lee et al. 2006 Choi and Kim 2013). However, there are relatively few reports of polymers containing mixed fillers for heat conduction purposes. To improve thermal conductivity of an epoxy, silicon... 

Lee Geon-Woong, Park Min, Kim Junkyung, Lee Jae Ik, and Yoon Ho Gyu. Enhanced thermal conductivity of polymer composites filled with hybrid filler. Composites Part A. 37 no. 5 (2006) 727-734. 

Yu L, Park JS, Lim Y-S, Lee CS, Shin K, Moon HJ, Yang C-M, Lee YS, Han JH (2013) Carbon hybrid fillers composed of carbon nanotubes directly grown on graphene nanoplatelets for effective thermal conductivity in epoxy composites. Nanotechnology 24 155604... 

In this section, the differences between using CVD hybrid fillers and physically mixed hybrid fillers in polymer composites were studied. It shows an interesting result with regard to the thermal and hardness properties of composites. The synergistic effects of two components in the hybrid fillers helped each other perform as fillers and reinforcements in polymer composites. The thermal conductivities and hardnesses of phenolic/CNT—alumina hybrid composites were studied. The CNT—alumina hybrid (HYB compound) was produced via the CVD method, which was discussed in Section 5.6. The phenolic/CNT—alumina hybrid composites were fabricated using hot-mounted molding. Thermal conductivity was measured using the transient plane source method with a Hot-Disk Thermal Constant Analyzer. Table 5.4 shows the sample description in this study. 

Yu, A., Ramesh, P., Sun, X., Bekyarova, E., Itkis, M.E., Haddon, R.C., 2008. Enhanced thermal conductivity in a hybrid graphite nanoplatelet — carbon nanotube filler for epoxy composites. Advanced Materials 20, 4740—4744. 

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. 

In this chapter, we discussed possible methods for the formation of electrically conducting biocomposites using proteinaceous sohd biomasses arising from leather industries as wastes. The proteinaceous collagen wastes were blended with natural polymers (chitosan or GG) and different fillers such as GrC and nanotubes (ie, BCNTs and FWCNTs) to form hybrid-conducting biocomposite films. The formed biocomposife films were found fo exhibit promising mechanical, thermal, and electrical properties. The thermal properties of both of the hybrid composite materials increase moderately with the increase in the addition of nanocarbons. The mechanical... 

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