PEEK composites

Example 3.9 For the 2 mm thick unidirectional carbon fibre/PEEK composite described in Example 3.6, calculate the values of the moduli, Poisson s Ratio and strains in the global direction when a stress of = 50 MN/m is applied. You should use... 

Fig. 2.18 illustrates the nature of the intensity profiles in pure polyetheretherke-tone (PEEK) and carbon fiber reinforced PEEK composites in the transmission and reflection modes, respectively. The quenched amorphous and slowly cooled crystalline components from PEEK can be separated. The three prominent diffraction peaks from the crystalline components in Fig. 2.18(a) correspond to the three uniform rings which can be detected in X-ray photographs. In contrast, no clearly measurable signal is identified from the PEEK amorphous phase independent of the carbon fiber content. 

Bucher, R.A, and Hinkley, J.A. (1992). Fiber/matrix adhesion in graphite/peek composites. J. Thermoplastic Composite Mater. 5, 2-13. 

Young, R.J., Day. R.J., Zakikhani, M. and Robinson, I.M. (1989). Fiber deformation and residual thermal stresses in carbon fiber reinforced PEEK. Composites Sci. Technol. 34, 243-258. 

Davies, P. Kausch, H.H., Williams, J.G. and 29 other researchers (1992). Round-robin interlaminar fracture testing of carbon fiber reinforced epoxy and PEEK composites. Composites Sci. Technol. 43, 129-136. 

Galiotis C., Melanitis, N., Batchelder D.N., Robinson I.M. and Peacock J.A. (1988). Residual strain mapping in carbon fiber PEEK composites. Composites 19, 321-324. 

As you can see, bone is a very complex composite material and, as snch, is difficult to artificially replicate. Nonetheless, there are a nnmber of materials of all types that are being nsed as bone replacements. Polymethylmethacrylate (PMMA), titaninm, graphite/polyethyletherketone (PEEK) composites, and tricalcinm phosphate, among... 

Figure 5.25 shows that the glass transition of composites containing carbon fibers may be affected by water uptake. The glass transition of carbon fiber/PEEK composite remains the same under diy and wet conditions. But carbon fiber/epoxy composites may experience a decrease in Tg as high as 77°C depending on the properties of the matrix resin." "... 

Orientation of fiber is detrimental to performance of composites which contain carbon fibers (Figures 11.16 and 11.17). T ensile strength of composites containing fibers oriented in a direction parallel to the surface is not affected by moisture content. Composites which have fibers oriented in a direction perpendicular to the surface, lose tensile strength as moisture increases (exception — carbon fiber/PEEK composite). Similar effects on tensile modulus, compression modulus and elongation have been observed. 

The introduction of fillers to PEEK creates a higher nucleation rate. The surface of carbon fibers and nuclei within the PEEK matrix compete for crystallization growth. Epitaxial transcrystalline growth was frequently observed on the fiber surface in carbon fiber reinforced PEEK composites. 

The antibacterial behaviour of cold sprayed HAp-Ag (silver-doped hydrox-yapatite)/PEEK composite coatings were investigated against Escherichia coli (DH5a) by Sanpo et al. (2009). The antibacterial activity was found to increase with increasing concentration of HAp-Ag nanoparticles. The precursor nanocomposite powders were deposited using rather mild cold spraying parameters (11-12 bars, preheated air temperature between 150 and 160 °C). 

It was observed that crystallinity in PEEK slowed the aging rate. This can also be seen in Figure 14.8, where p is plotted as a function of the undercooling (T - T ). Close to T the rates of aging for the amorphous, semi-crystalline PEEK and PEEK composites were similar but,... 

The influence of physical aging on the comparative and intrinsic toughness of PEEK and PPS carbon-fiber composites was determined by Ma et al. [1992]. Both types exhibited a loss of toughness with increase in aging time and temperature. The PEEK composites tended to retain more impact toughness but after aging were less ductile than the PPS composites. 

Carbon and glass-fiber reinforced PEEK has been used with advanced plastics technology in the redesigning of the helicopter blades profile, improving aerodynamic properties, and reducing overall weight [37]. The use of PEEK composites in the RAF Linx helicopter enabled it to break the world helicopter speed record. 

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. 

Martin RH, Murri GB. Characterization of mode I and mode II delamination growth and thresholds in AS4/PEEK composites. In Garbo SP, editor. Composite materials testing and design, vol. 1059. ASTM Special Technical Publication 1990. pp. 251—70. http // dx.doi.org/10.1520/STP24115S. 

Jar P-YB, Mulone R, Davies P, Kausch HH. A study of the effect of forming temperature on the mechanical behavior of carbon-fibre/PEEK composites. Compos Sd Technol 1993 46 7-19. http //dx.doi.org/10.1016/0266-3538(93)90076-S. 

Hamada H, Ramakrishna S, Satoh H. Crushing mechanism of carbon fibre/PEEK composite tubes. Composites 1995 26 749-55. 

R. K. Goyal, A. N. Tiwari, U. P. MuUk, and Y. S. Negi. Effect of aluminum nitride on thermomechanical properties of high performance PEEK. Composites Part A, 38(2) 516-524, February 2007. 

M. C. Kuo, C. M. Tsai, J. C. Huang, and M. Chen. PEEK composites reinforced by nano-sized Si02 and AI2O3 particulates. Mafe/ Chem. Phys., 90(1) 185-195, March 2005. 

K. Fujihara, Z.-M. Huang, S. Ramakrishna, K. Satknanantham, and H. Hamada. Performance study of braided carbon/PEEK composite compression bone plates. Biomaterials, 24(15) 2661-2667, July 2(X)3. 

Qiao HB, Guo Q, Tian AG, Pan GL, Xu LB. A study on friction and wear characteristics of nanometer AI2O3/PEEK composites under the dry sliding condition. Tribol Int 2007 40(1) 105-10. 

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