Short fibers technology

The recorded history of short fiber technology starts over two thousand years ago with asbestos fibers and reaches into the future with silicon nano-whiskers and carbon nanotubes. Asbestos is derived from the solid phase, but today, the most important short inorganic fibers are derived from the vapor phase. 

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. 

This section will review selected papers on the behavior of composites reinforced with more or less isotropically dispersed short fibers. More detailed technological and theoretical mechanical discussions, as well as additional information on composites containing continuous unidirectional or cross-plied fibers, is given by Ashton et al. (1969), Broutman and Krock (1967, 1974), Chamis (1974a), Corten (1966, 1971), Hattori (1970), Parkyn (1970), Schwartz and Schwartz (1968), Tsai et al (1969), and Wu (1974), as well as in the general literature. ... 

Bader MG, Hill AR (1993) Short fiber composites. In Chou T-W (ed) Material science and technology - a comprehensive treatment, vol 13 structure and properties of composites. VCH, Weinheim, Germany, pp 291-338... 

The main stream of wood fiber PP composites is short fiber reinforced, suitable for typical thermoplastic processing. The main steps of this technology are (1) pre-mixing, (2) plastic transformation of the melt (typically sheet extrusion), and (3) thermoforming (vacuum- or pressureforming) of the sheet. 

The net-shape-nonwoven (NSN) technology allows manufacturing three-dimensional structures from short fibers in a layer-by-layer approach as seen in Fig. 12.3 [44]. 

Figure 4.7 and Table 4.2 are reprinted from Composites Science and Technology, Vol. 67, 2007, Authors Zhang H, Zhang Z and Fiiedrich K, Title Effect of fiber length on the wear resistance of short fiber reinforced epoxy composites, pp. 222-230, Copyright (2011), with permission from Elsevier Ltd. 

Tucker, C. L. and Liang, E. Stiffness predictions for unidirectional short-fiber composites Review and evaluation. Composites Science and Technology, 59,655-671 (1999). 

Compression molding (short fibers, 5-50 mm) Semi-finished sheets of glass mat thermoplastics are heated and placed in the lower part of the mold in a fast press. The press is quickly closed and pressure is applied so that the material can flow to fill the mold. Technology is also available where the hot molding compound reaches the mold from an extruder. 

By contrast, it is current technology to apply fracture mechanics with several modifications to short fiber-reinforced composites. 

Fu, S.Y., Hu, X., Yue, C.Y., 1999. The flexural modulus of misaligned short-fiber-reinforced polymers. Composites Science and Technology 59, 1533—1542. 

Controlling short fiber orientation in extruded rubber hoses with converging-expanding dies application in the moving die technology to produce curve hoses. 

E. Zainudin, S. Sapuan, S. Sulaiman and M. Ahmad, Fiber orientation of short fiber reforced injection molded thermoplastic composites a review . Journal of injection molding technology 6(1), 1 (2002). 

Staple is produced by cutting a crimped tow into short lengths (usually 4—5 cm) resembling short, natural fibers. Acetate and triacetate staple are shipped in 180—366 kg bales, but production is quite limited. Conventional staple-processing technology appHed to natural fibers is used to process acetate and triacetate staple into spun yam. 

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