Elastic modulus epoxy resin

In Figure 5.24 the predicted direct stress distributions for a glass-filled epoxy resin under unconstrained conditions for both pha.ses are shown. The material parameters used in this calculation are elasticity modulus and Poisson s ratio of (3.01 GPa, 0.35) for the epoxy matrix and (76.0 GPa, 0.21) for glass spheres, respectively. According to this result the position of maximum stress concentration is almost directly above the pole of the spherical particle. Therefore for a... 

The relevant properties of these materials for the torsional-mechanical analysis are listed in Table 8.11. On the basis of specific elastic modulus and specific shear modulus, the best materials are the graphite-fiber-reinforced epoxy resin, followed by either of the alloys, then the Kevlar fiber-reinforced epoxy. The chopped glass sheet molding compound is obviously not a good choice. 

In summary, we can first say that there is no significant evidence that the low surface energy siloxane-modified epoxies reduce friction compared with the unmodified epoxy or the ATBN- and CTBN-modified epoxies. Based on the results of the steel ball-on-epoxy experiments, the most significant effect of the siloxane modifiers is the reduction of the elastic modulus associated with large closely spaced domains. The longer initiation times and lowest wear rates observed for the siloxane-modified epoxies were generally associated with a lower modulus. Epoxy modified with the CTBN of 18% AN content also showed lower wear rates with lower modulus but, in contrast with the siloxane-modified resins, had shorter initiation times with lower modulus. 

The most successful application of the RIM-process is in the production of polyurethane-based materials. Other systems, such as composites based on polycaproamide, epoxy resins, and unsaturated polyesters can also be processed by reactive injection molding. New reactive systems have also been specially created for the RIM-process260 because of the exceptional opportunities it offers for manufacture of finished articles from engineering plastics with a high modulus of elasticity and impact strength. The automotive industry, which is the main customer for RIM-articles, can utilize this technology to manufacture of massive parts such as body panels, covers, wings, bumpers and other made of newly developed plastics. 

It is known that in the glassy state below the glass transition temperature the physical properties of epoxy resin as well as other amorphous polymers are generally little dependent on temperature and structure 1,28). Also, the modulus of elasticity (E) does only weakly depend on the crosslinking density. 

The use of the above equations is shown in Fig. 25 where the calculated and measured [45] Young s modulus of a crosslinked epoxy resin filled with silica (Si02) particles are compared. The elastic properties of the filler and matrix are [44]... 

Calculate (a) the modulus of elasticity, (b) the tensile strength, and (c) the fraction of the load carried by the fibers for a continuous glass fiber-reinforced epoxy resin, with 60% by volume E-glass fiber, stressed under isostrain conditions. The tensile strength and modulus of the fibers are 1800 MPa and 76 GPa, respectively, and the values of these quantities for the matrix are 60 MPa and 2.4 GPa, respectively. 

Samples of epoxy resin filled with glass microspheres have a reduced elastic modulus after water immersion. The loss of elastic modulus is more pronounced as... 

The filler effects on the chemoviscosity of thermosetting resins have not been studied extensively, but are vital to understanding the rheology of filled thermosets. For example, the effects of filler concentration on viscosity can be used in process control to monitor batch-to-batch variations or to provide essential information for research into alternative filler/resin batches. Ng and Manas-Zloczower (1993) examined an epoxy-resin system with silica filler and established that the elastic modulus of the resin can be expressed in terms of... 

The preparation of composite materials in general is a very important appHca-tion of the mechanical properties of nanodiamond. With many polymers like caoutchouc, polysiloxanes, fluoroelastomers polymethacrylates, epoxy resins, etc., composites with markedly improved mechanical characteristics have already been obtained from the noncovalent incorporation of nanodiamond by simple admixing during polymerization. The modulus of elasticity, the tensile strength, and the maximal elongation of the material all increase upon this modification. Depending on the basic polymer, just 0.1-0.5% (w/w) of nanodiamond are required to achieve this effect (Table 5.3). Polymer films can also be reinforced by the addition of nanodiamond. For a teflon film with ca. 2% of nanodiamond added, for example, friction is reduced at least 20%, and scratches inflicted by mechanical means are only half as deep as in neat teflon. 

Compute the modulus of elasticity of a composite consisting of continuous and aligned carbon fibres of 60 % weight fraction in an epoxy resin matrix under (a) longitudinal and (b) transverse loading. The modulus of elasticity of the carbon fibres is 290 GPa and the density is 1785 kg m. The elastic modulus of the resin is 3.2 GPa and its density is 1350 kg m. ... 

Adding small amounts of reactive flexibilizers to an epoxy resin can reduce the modulus of elasticity, glass-transition temperature (Tg), and CTE of an otherwise hard and brittle material. Rubber-like materials such as a carboxyl-terminated... 

It should be noted that, for all the resins considered, the specific heat does not depend on cross-linking or the chemical structure below 100 K. This can be explained by the Debye theory, which states that the specific heat is a function only of the oscillator density, N, and 0/T. 6 is the Debye temperature, which can be determined by elastic parameters, such as Young s modulus, E, N is approximately equal for all resins, since they have nearly equal densities. At low temperatures, roughly the same value of E is asymptotically reached by the epoxy resins. 

Young s Modulus. Young s moduli, E, for several resins are plotted vs. temperature in Fig. 7. Young s moduli were determined from stress-strain diagrams. At 4K, their values are within 10%. Therefore, the low-temperature values of E do not depend markedly on the detailed chemical structure. It must be emphasized that epoxy resins are energy-elastic and have a nearly linear stress-strain behavior to fracture at low temperatures. No rate dependence was found over several decades. This is not true for many high polymers, such as polyethylene (PE), which are not cross-linked. PE behaves viscoelastically, even at 4 K [%... 

Five-centimeter-diameter tubular samples with a 0.64-cm (4-in.) wall thickness were also prepared to screen epoxy resins for a study of the effects of fiber content and void volume on the allowable stress and elastic modulus of the samples. Samples were made with Type 410AAE fiberglass and an epoxy resin binder. Each was manufactured with helically and circumferentially wound filaments in one of the following patterns (from inner surface layer to outer surface layer) sample 1 o-xxxx-o-xxxx-o. .. and sample 2 xx-oooo-xx-oo-xx. .., where the symbol o represents filaments wound at 88-89 to the pipe axis x represents filaments at 45 . 

Let us consider the elastic properties of epoxy polymer thin films on substrates with various surface energies. The elasticity of the boundary layers and its contribution to the elasticity of the film on the substrate were assessed by the dependence of the modulus of elasticity on the thickness of the polymeric coating formed on high-energy (aluminum) and low-energy (polyethylene terephthalate) surfaces. ED-20 epoxy resin (molecular weight 420, epoxy number 21.6) was selected... 

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