Short carbon fiber

Short fiber reinforcement of TPEs has recently opened up a new era in the field of polymer technology. Vajrasthira et al. [22] studied the fiber-matrix interactions in short aramid fiber-reinforced thermoplastic polyurethane (TPU) composites. Campbell and Goettler [23] reported the reinforcement of TPE matrix by Santoweb fibers, whereas Akhtar et al. [24] reported the reinforcement of a TPE matrix by short silk fiber. The reinforcement of thermoplastic co-polyester and TPU by short aramid fiber was reported by Watson and Prances [25]. Roy and coworkers [26-28] studied the rheological, hysteresis, mechanical, and dynamic mechanical behavior of short carbon fiber-filled styrene-isoprene-styrene (SIS) block copolymers and TPEs derived from NR and high-density polyethylene (HOPE) blends. 

Fu SY, Lauke B, Mader E, Yue CY, Hu X. Tensile properties of short-glass-fiber- and short-carbon-fiber-reinforced polypropylene composites. Composites Part A Applied Science and Manufacturing. 2000 31(10) 1117-25. 

Zoltek User s Guide for Short Carbon Fiber Composites, (June 2000), Zoltek Companies, Inc, St Louis, MO 63044, USA, www.zoltek.com... 

One typical example of carbon/carbon composite plates is that made by Oak Ridge National Laboratory (ORNL) in the United States [12]. The composite preform was fabricafed by a slurry-molding process from fhe mixed slurry befween short carbon fibers (graphite fibers were also added in some sample plates) and fhe phenolic resin. The mass rafio between fiber reinforcement and phenolic matrix is 4 3. The phenolic matrix improves the mechanical properties and dimensional stability of the plate. A subsequent vacuum molding process was utilized to fabricate composite plates and fluid fields with relatively high resolution (Figure 5.3, [11]). 

Caneiro, O. S., and J. M. Maia, Rheological behavior of (short) carbon fiber/thennoplastic composites. Part II The infinence of matrix type, Polym. Composites, 21(6), 970 (2000). 

An injection molded bar contains 20% by volume of short carbon fibers in a matrix of nylon 6,6. Take the tensile strengths of the carbon fibers and the nylon to be 3200 MPa and 70 MPa, respectively, and assume the shear strength of the carbon fiber-nylon interface to be 32 MPa. The tensile moduli of nylon 6,6 and carbon fibers are 2.7 GPa and 230 GPa, respectively. Assume that the fibers are all of length 400 p.m and diameter 6 p.m and are perfectly aligned along the axis of the bar. 

Galvanic corrosion of polyacrylnitrile (PAN) and pitch-based short carbon fibers in polyetheretherketone (PEEK) composites were studied by Gebhard et al. [40]. Galvanic corrosion of carbon-fiber compounds can occur in contact with a steel electrode. The effects ranged from initial breakdown and cracking, to complete dissolution. 

Abu Abu Bakar, M. A., Ahmad, S., Kuntjoro, W. Effect of matrix modification on the mechanical properties of short carbon fiber-reinforced epoxy composites. J. Reinforced Plast. Compos. 30 (2011) 357-361. 

IlWhi White, K. L., Sue, H.-J. Electrical conductivity and fracture behavior of epoxy/polyamide-12/ multiwalled carbon nanotube composites. Polym. Eng. Sci. 51 (2011) 2245-2253. llZha Zhang, G., Rasheva, Z., Karger-Kocsis, J., Burkhart, T. Synergetic role of nanoparticles and micro-scale short carbon fibers on the mechanical profiles of epoxy resin. eXPRESS Polym. Lett. 5 (2011) 859-872. 

The addition of short carbon fibers, glass fiber, and hybrid carbon/glass fibers to recycled PET/PEN blends improves the tensile strength and the Young modulus in a better way than the addition of PEN into recycled PET [82]. Therefore, it was concluded that the mechanical properties of recycled PET can be enhanced more efficiently with the reinforcement by short fibers. 

Several recent reports describe using clay or other inorganic fillers to form CP composites. Polyani-line-polypyrrole composite coatings containing clay or yttria stabilized zirconia were electrodeposited onto AA 2024-T3 [158], with improved corrosion resistance of the substrate. Similarly, particulate-filled polyaniline and polypyrrole films on AA 2024-T3 were prepared electrochemically using a variety of fillers, including clay, carbon black, short carbon fiber, zirconia, and silica [159]. Again, enhanced corrosion performance for these composites was observed. 

M. Krodel et al., Short Carbon-Fiber Reinforced Ceramic—CeSiC—for Optomechanical Applications, presented at the SPIE Optomechanical Design and Engineering Conference, Seattle, WA, July 7-9, 2002 (2002). 

Three major breakthroughs in process technology have recently been made. These processes facilitate the growth from a liquid phase. They inciude the formation of (1) InP, InAs and GaAs whiskers [18] from other organic soivents by a soiution-iiquid-soiid phase transformation, (2) short carbon fibers from liquid pitch melts by centrifuging [19], and (3) silver nanowires by a novel self-assembly process [71]. Micro- and nanopillars (or micro-and nanocolumns) are a new class of short inorganic fibers. They are... 

Short carbon fibers with diameters of 10 pim grow by iron particle catalyzed chemical vapor deposition from methane, natural gas [7] [25], benzene [26], or acetylene [23] as shown in... 

Until 1987, the only route to short carbon fibers was a metal catalyzed chemical vapor deposition. Since then, a novel process has become available [19] that facilitates the growth of discontinuous carbon fibers from mesopitch by a continuous liquid phase centrifuge process. Pitch may be considered to consist of a complex mixture of polycyclic aromatic hydrocarbons. It is a semisolid at room temperature but, depending on the composition, it melts above 100°C. Pitch has two phases, a high melting anisotropic, and a low melting isotropic, phase. The anisotropic phase, called mesopitch, is preferred for this process. 

The technology of growing short carbon fibers from the vapor phase dates back to 1889 when a patent [46] issued claiming their growth by using iron catalyzed pyrolysis of methane. About a hundred years later a continuous process has become commercially available [47-48] potentially opening the door to commercial development [51]. 

A report by NIOSH [43], investigating a Composites Department at a New Hampshire Ball Bearings factory in Laconia, revealed that the dimensions of airborne carbon fibers were approximately 45 pm in length and 6 pm in diameter. Bulk dust samples comprised long and short carbon fibers with a uniform diameter of approximately 9 pm, with relatively smooth sides and while some fibers had pointed ends, the ends were not particularly sharp or jagged. A few operatives reported a minor transient skin itch, which was attributed to carbon fibers on exposed skin. 

The impact properties of short carbon fiber reinforced PA6.6 have been examined [111] as well as the microstructure of PA6,6 layers in cfrp [112]. The abrasive wear of short carbon-fiber reinforced PA6,6 has been reported [113]. 

Zam Ishak, Berry JP, Impact properties of short carbon-fiber- reinforced nylon 6,6. Polym Eng Sci, 33(22), 1483-1488, 1993. 

Lee DJ, On studies of tensile properties in injection molded short carbon fiber reinforced PEEK composite, KSME J, 10(3), 362-371, 1996. 

Hanchi J, Eiss NS, Dry sliding friction and wear of short carbon-fiber-reinforced polyetheretherketone (PEEK) at elevated temperatures. Wear, 203, 380-386, 1997. 

Figure 15.6 Load deflection curve of unreinforced Pyrex and short carbon fiber reinforced Pyrex. Source Reprinted with permission from Sambell RAJ, Bowen DH, Phillips DC, J Mater Sci, 7, 663-675, 1972. Copyright 1972, Springer.

The load deflection curve for short carbon fiber reinforced Pyrex is compared with the unreinforced matrix in Figure 15.6 and the contribution of the fiber towards toughening, despite a reduction in flexural strength arising from the poor bond of the fibers with the matrix, is clearly seen. 

Chen PW, Chung DDL, Concrete reinforced with up to 0.2-percent of short carbon fibers. Composites, 24(1), 33 52, 1993. 

Yang XM, Chung DDL, Latex-modified cement mortar reinforced by short carbon-fibers. Composites, 23(6), 453-460, 1992. 

Short carbon fiber Al matrix composite material can be prepared by extrusion of powder mixtures [81]. 

Pai and workers [140] used a semi solid slurry process for making short carbon fiber dispersed A1 alloy matrix composites. 

Simancik F, Jangg G, Degischer HP, Short carbon fiber-aluminum matrix composite material prepared by extrusion of powder mixtures. Journal de Physique, IV 3,(C7), Part 3, 1775-1780, 1993. 

Pai BC, Pillai RM, Kelukutty VS, Rao HS, Soman T, Pillai SGK, Sukumaran K, Satyanarayana KG, Ravikumar KK, Gupta AK, Sikand R, Semi-solid slurry process for making short carbon-fiber dispersed aluminum-alloy matrix composites, J Mater Sci Lett, 13(17), 1278-1280, 1994. 

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