Carbon fiber composites mechanical properties

Effect of size and surface treatment of carbon fibers on mechanical properties of magnesium matrix composites ... 

Piggott M.R., Lam P.K., Lim J.T. and Woo M.S. (1985). The internal pressure, mechanical properties and water absorption of carbon fiber composites with spiro-epoxy copolymer matrices. Composites Sci. Technol. 23, 247-262. 

The complex sorption behavior of the water in amine-epoxy thermosets is discussed and related to depression of the mechanical properties. The hypothesized sorption modes and the corresponding mechanisms of plasticization are discussed on the basis of experimental vapor and liquid sorption tests, differential scanning calorimetry (DSC), thermomechanical analysis (TMA) and dynamic mechanical analysis. In particular, two different types of epoxy materials have been chosen low-performance systems of diglycidyl ether of bisphenol-A (DGEBA) cured with linear amines, and high-performance formulations based on aromatic amine-cured tetraglycidyldiamino diphenylmethane (TGDDM) which are commonly used as matrices for carbon fiber composites. 

Poly(vinyl) alcohol (PVA) is a semi-crystalline polymer, which is already widely used for various applications, either under the form of films or fibers. Compared to other polymers, as it is water-soluble at high temperature, it is easy to process from aqueous solutions. Carbon nanotubes can also be dispersed or solubilized in water via different functionalization approaches. It was quite natural for researchers to try to mix carbon nanotubes and PVA to improve the properties of the neat polymer. In this chapter, we will first examine the different methods that have been used to process CNT/PVA composites. The structures and the particular interaction between the polymer and the nanotube surface have been characterized in several works. Then we will consider the composite mechanical properties, which have been extensively investigated in the literature. Despite the number of publications in the field, we will see that a lot of work is still to be done for achieving the most of the exceptional reinforcement potential of carbon nanotubes. 

Figure 9.13 shows the effect of filler concentration on torque. The smallest increase was due to magnesium carbonate and the largest due to the presence of glass fibers. The mechanical properties of filled composites are substantially improved by additions of magnesium carbonate, wollastonite and glass fiber. The most important improvement is in creep resistance (Figures 6.68 and 8.69). 

Next to mechanical properties, the most important characteristics of a carbon-carbon composite(C/C) are thermal conduction and thermal expansion. In this paper, several investigations have been made into carbon fiber arrangement relationships for different carbon-carbon composite materials. Pitch-derived carbon matrix-carbon fiber composites have been used, processed by means of the hot isostatic pressing (HIP) technique for converting pitch into a dry carbon fiber preform. Repeated HIP cycles are required to build the composite matrix up to an acceptably high density/low porosity for deployment in severely ablative environments. 

The physical properties of the blends and mechanical/fracture characteristics of their carbon fiber composites in the case of a commercial cyanate/bismaleim-ide blend could be substantially enhanced by incorporation of propenyl functional cyanate ester which is capable of leading to linked IPNs. Various blends of a commercial BMI mixture (i.e., compimide-353, components shown in Scheme 22), a cyanate ester (AroCy B-30), and a comonomer with allyl group, typically 2,2-bis(3-allyl-4-cyanatophenyl) propane (BACP) or one with propenyl... 

The laminates of tiK carbon-fiber composite were first characterized by acoustic NDI (C-scan) and optical microscopy to evaluate their quality. Scanning electron microsctqiy (SEM) was used to evaluate laminate quality and nanoparticle distributimi using a Philips XL30 ESEM TMP scanning electron microscope. Mechanical tests fm tiie carbon-fiber composite were selected to measure resin-dominated properties. These tests were transverse four-point flexure with a qian-to-deptii ratio of 32 1 and longitudinal four-point flexure with a qi>an-to-depdi ratio of 16 1 designed to induce mic lane shear failure. Ten qiecimens were tested for each material type and condition. 

Polymer composites. The composite research at the Institute is led by Prof. Wu Renjie, Deputy director of the Institute. Chen, et al. (14), studied the effect of oxidation of carbon fiber on the wettability by the binder resin. With the aid of ESCA, they showed that the Q/C ratio on the fiber surface increased with the oxidation time. The interlaminar shear strength also increased correspondingly. Cai Weizhen and her colleagues showed me their exceptional setup for a carbon-fiber composite study. They built their own torsion pendulum for the study of dynamic mechanical properties of the composite and a contact angle goniometer for the study of the composite interface. It was apparent that surface treatment of carbon fiber was their major concern. 

Tibbetts, G. McHugh, J. J. Mechanical properties of vapor-grown carbon fiber composites with thermoplastic matrices. J. Mater. Res. 14, 2871-2880 (1999). 

Jenkins SD, Emmerson GT, McGrail PT, Robinson RM, J Adhesion, 45(1-4), 15-27, 1994. Labronici M, Ishida H, Dynamic mechanical characterization of PMR polyimide/carbon fiber composites modified by fiber coating with silicones. Composite Interfaces, 5(3), 257-275,1998. Labronici M, Ishida H, Effect of the silicone interlayer on mechanical properties of carbon fiber reinforced PMR-15 polyimide composites. Composite Interfaces, 5(2), 87-116, 1998. 

Krucinska I, Evaluation of the intrinsic mechanical properties of carbon fibers. Composite Sci Technol, 41(3), 287-301, 1991. 

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