Reinforced polymer composites

The manufacture of fiber reinforced composites involves the combination of the fiber reinforcement and a liquid precursor to the matrix in a mold, followed by solidification of the liquid and formation of the matrix. This solidification can be the result of chemical reac- 

Although the reinforcing fibers may be present in the liquid precursor prior to dispensing, better properties are typically obtained when the fibers are initially present in the mold as a preform. The liquid is then dispensed into the mold such that the final matrix fills the mold and surrounds the fibers. Preforms may be arranged as mats or meshes. The fibers within the preform may be randomly oriented or may be oriented in one or more directions. 

The performance of composites is influenced by many factors, including the amount of reinforcement present relative to the matrix, referred to as fiber loading and the degree of contact between the fibers and the matrix. Both strength and stiffness tend to be improved by an increase in fiber loading and by increased contact between the phases. 

To ensure sufficient contact between the fibers and the matrix, it is desirable to use a liquid precursor with a low viscosity. Reactive liquids are usually preferred over thermoplastics due to the low viscosity of liquids relative to polymer melts. The reactive liquid is typically a multi-component mixture. The reactive liquid may contain a monomer and an activator, which will cause the monomer to polymerize into a solid polymer matrix. 

In RIM processes, two or more reactive components are mixed together, starting the reaction between the components before the mixture is dispensed into the mold. This tends to increase the viscosity of the liquid that is dispensed due to an increase in molecular weight of the polymers or pre-polymers formed in the initial reaction. An increased viscosity can prohibit complete filling of the mold and permeation of the preform. This tends to decrease the adhesion between the matrix and the fibers. Poor interfacial adhesion between the reinforcement and matrix phase can cause a material to have less than desirable stiffness and strength. 

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Though short fiber-reinforced mbber composites find application in hose, belt, tires, and automotives [57,98,133,164] recent attention has been focused on the suitability of such composites in high-performance applications. One of the most important recent applications of short fiber-mbber composite is as thermal insulators where the material will protect the metallic casing by undergoing a process called ablation, which is described in a broad sense as the sacrificial removal of material to protect stmcrnres subjected to high rates of heat transfer [190]. Fiber-reinforced polymer composites are potential ablative materials because of their high specific heat, low thermal conductivity, and ability of the fiber to retain the char formed during ablation [191-194]. 

Ramsteiner, F. and Theysohn, R The influence of fiber diameter on the tensile behavior of short-glass fiber reinforced polymers, Composites Sci. Technol., 24, 231-240 (1985). 

Fu, S. and Lauke, B Effects of fiber length and fiber orientation distributions on the tensile strength of short-fiber-reinforced polymers, Composites Sci. Technol., 56, 1179 (1996). 

Brink, A. E., Owens, J. T., Oshinski, A. J. and Pecorini, T. J., Process for preparing high strength fiber reinforced polymer composites, US Patent 6 048 922, 2000. 

Another approach to exploit the properties of nanocarbons consists in integrating them in standard fiber-reinforced polymer composites (FRPC). The rationale behind this route is to form a hierarchical composite, with the nanocarbon playing a role at the nanoscale and the macroscopic fiber providing mainly mechanical reinforcement. This strategy typically aims to give FRPCs added functionality, improve their interlaminar properties and increase the fiber surface area. The first two properties are critical for the transport industry, for example, where the replacement of structural metallic... 

Ranby and Shi also studied hyperbranched methacrylated polyesters and their use in photopolymerizations of films and fiber-reinforced polymer composites. The resins were found to have low viscosities and higher curing rates than those of corresponding linear unsaturated polyesters [131-133]. 

Drumm, C.A. and Ulicny, J.C. (1989). Analysis of coating on glass fiber reinforcements. Polym. Composites 10. 44-51. 

Desaeger, M. and Verpoest, I. (1993). On the use of the microindentation test technique to measure the interfacial shear strength of fiber reinforced polymer composites. Composites Sci. Technol. 48, 215-226. 

McGarry, F.J. (1969). The fracture of polymers and fiber reinforced polymer composites. In Proc. AlAAj ASME lOlh Structures, Structural Dynamics Mater. Conf., New Orleans, pp. 456-471. 

BFRP boron fiber reinforced polymer composites... 

As first described in Section 1.4.2, there are a number of ways of further classifying fiber-matrix composites, such as according to the fiber and matrix type—for example, glass-fiber-reinforced polymer composites (GFRP) or by fiber orientation. In this section, we utilize all of these combinations to describe the mechanical properties of some important fiber-reinforced composites. Again, not all possible combinations are covered, but the principles involved are applicable to most fiber-reinforced composites. We begin with some theoretical aspects of strength and modulus in composites. 

M.R. Kessler, S.R. White, and B.D. Myers, Catalyzed reinforced polymer composites, US Patent 6 750 272, assigned to Board of Trustees of... 

Lee H, Mall S, He P, Shi DL, Narasimhadevara S, Yeo-Heung Y, Shanov V, Schulz MJ (2007) Characterization of carbon nanotube/nanofiber-reinforced polymer composites using an instrumented indentation technique. Composites Part B 38 58-65... 

The manufactured 90 mm x 90 mm x 10 mm three-layered B4C/B4C-30wt%SiC tiles were tested as armor [67], The photographs of the experiment set-up of the ballistic test as well as a residual impression in the clay box that was used as one of the criteria in the ballistic performance of laminates are shown in Fig. 7.17. The ballistic penetration tests were performed to evaluate the ballistic performance of the laminates. Depth of penetration tests were used to evaluate the ballistic performance of the composite laminates. In addition, pure B4C monolithic ceramics were used as a standard for the test. Test panels were made using the three-layered B4C/B4C-SiC laminate and B4C monolithic ceramic material as the hard face. While the B4C monolithic tile had 100% of its theoretical density, the three-layered B4C/B4C-30wt%SiC laminates had about 3-4% of porosity. A commonly used Spectra fiber-reinforced polymer composite was used as backing plates. The targets were mounted on clay and the projectile was shot at the target at a specific velocity. 

Hsiao, Kuang-Ting, et al., Use of Epoxy/Multiwalled Carbon Nanotubes as Adhesives to Join Graphite Fiber Reinforced Polymer Composites, Nanotechnology, vol. 24, July 2003, pp. 791-793. 

These efforts indicated that the sidewall functionalization effectively enhances the tensile strength and tensile modulus by improving dispersion and interfacial bonding in SWNTs reinforced polymer composite. 

Galiotis, C., Laser Raman spectroscopy, a new stress/strain measurement technique for the remote and on-line non-destructive inspection of fiber reinforce polymer composites. Mater. TechnoL, 8, 203, 1993. 

Blackman, B.R.K., Brunner, A.J., (1998) Mode I Fracture Toughness Testing of Fibre-Reinforced Polymer Composites Unidirectional versus Cross-ply Lay-up , Proceedings 12" European Conference on Fracture ECF-12 Vol. Ill, Fracture from Defects, EMAS Publishing, pp. 1471-1476. 

Paraffins, PE and metals, such as Pb and Sn, have microhardness values below 100 MPa. Semicrystalline polyoxymethylene, PET, chain-extended PE, poly(ethylene 2,6 naphthalate) and metals, such as Al, Au, Ag, Cu and Pt, have values between 100 and 300 MPa. The microhardness values of carbon-fibre-reinforced polymer composites are about 900 MPa and those for the common metals Zn and Co are 2000 and 4000 MPa, respectively, while for white steel it is 5000 MPa. 

Recently, much attention is being placed on fibres-reinforced/polymer systems as subjects of study. It was caused by increasing emphasis on high performance reinforced polymer composites. The concept of acid/base interactions across the fibre/polymer interface was noted particularly and the relevance of acid/base theories to the behaviour of po-... 

FIG. 4. Conceivable applications of natural fiber reinforced polymer composites in cars (NMT=natural fiber mat reinforced thermoplastic TP NF=natural fiber reinforced thermoplastic)... 

FIG. 5. Conceivable applications of natural fiber reinforced polymer composites in... 

TABLE I. EB-PROCESSED MINERAL REINFORCED POLYMER COMPOSITES... 

U.S. Pat. No. 4,820,749 (April 11, 1989). A.D. Beshay. Reinforced polymer composites with wood fibers grafted with silanes. 

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