Glass tensile modulus

Polymer [molecular weight]0 Glass Transition Tg CC) Decomposition onset peak CC) (V) Tensile strength (kg/cm2) Tensile modulus (kg cm ) Elongation at yield break (%) (%) Solubility... 

Figure 6.10. Glass, aramid and carbon fibre reinforced composites tensile modulus versus tensile strength examples...

Resin Tensile Modulus, MPa Impact Strength, 1/cm Melting Temperature (U °C (semicrystalline) Glass Transition Temperature (g, °C (amorphous) Applications... 

Consider, then, a composite material that consists of 60% by volume continuous, uniaxially-aligned, glass fibers in an epoxy matrix. Take the tensile modulus and Poisson s ratio of glass to be 76 GPa and 0.22, respectively, and of the epoxy to be 2.4 GPa and 0.34, respectively. Take the coefficients of thermal expansion to be 5 x 10 and 60 X 10 K for glass and epoxy, respectively. 

Poisson s ratio for the off-axis loaded lamina, v y, can also be derived. The relative tensile modulus, E jEi, shear modulus, Gj jGi2, and Poisson s ratio, v y, are plotted as a function of the angle of rotation, 9, for a glass-fiber-reinforced epoxy lamina and a graphite-fiber-reinforced epoxy lamina in Figures 5.120a and 5.120b, respectively. 

The mechanical properties of Teflon AF differ from those of the semicrystalline Teflon . Below the glass transition temperature the tensile modulus is higher (1.5 GPa) and elongation to break lower (5-50%). Similarly, below the Tg, creep is generally less than that normally observed for PTFE and shows much less variation with temperature. 

For many years, it has been known that a small quantity of plasticizer acts as an anti plasticizer for polyvinyl chloride (PVC). During a recent search for effective plasticizers for polycarbonate, W. J. Jackson and J. R. Caldwell found several groups of compounds which acted as antiplasticizers. They increased the tensile modulus and strength and reduced the elongation of polycarbonate films. In contrast to plasticizers, these antiplasticizers affected glass transition temperature quite differently. Their mechanism is explained by the fact that they either increase crystallinity or reduce the mobility of the polymer chain through the bulkiness of their molecules. 

Since each of these polycarbonates had exceptionally high glass transition temperatures—256° and 290°C., respectively—it was possible to add appreciable amounts of antiplasticizers without depressing the glass transition temperatures to room temperature or lower. In addition, since the bisphenol II polycarbonate already had a relatively high tensile modulus (4.7 X 105 p.s.i.), it was of interest to determine how much this modulus could be increased. 

Here we have conducted experiments to develop an understanding of how the commercial size interacts with the matrix in the glass fiber-matrix interphase. Careful characterization of the mechanical response of the fiber-matrix interphase (interfacial shear strength and failure mode) with measurements of the relevant materials properties (tensile modulus, tensile strength, Poisson s ratio, and toughness) of size/matrix compositions typical of expected interphases has been used to develop a materials perspective of the fiber-sizing-matrix interphase which can be used to explain composite mechanical behavior and which can aid in the formulation of new sizing systems. 

The strength of adhesion between the fiber and matrix could also be expected to play a role in this change in failure mode. The interfacial testing system (ITS) provides comparative data on the interfacial shear strengths of the bare and sized E-glass fibers in real composites. A handbook value of 76 GPa [19] was used for the tensile modulus of E-glass fibers and the matrix shear modulus was previously determined as 1.10 GPa. Table 4 lists the mean interfacial shear strength, standard deviation (SD), and number of fiber ends tested for the two fiber types. 

Figure 9.16 Increase in tensile modulus as a result of the presence of short glass fibres.

Dynamic Mechanical Properties. Figure 15 shows the temperature dispersion of isochronal complex, dynamic tensile modulus functions at a fixed frequency of 10 Hz for the SBS-PS specimen in unstretched and stretched (330% elongation) states. The two temperature dispersions around — 100° and 90°C in the unstretched state can be assigned to the primary glass-transitions of the polybutadiene and polystyrene domains. In the stretched state, however, these loss peaks are broadened and shifted to around — 80° and 80°C, respectively. In addition, new dispersion, as emphasized by a rapid decrease in E (c 0), appears at around 40°C. The shift of the primary dispersion of polybutadiene matrix toward higher temperature can be explained in terms of decrease of the free volume because of internal stress arisen within the matrix. On the other... 

Comparison with Asbestos and Glass. Tables III, IV, V, and VI catalog the properties obtained when the two polystyrenes were reinforced with asbestos and glass. Table VII compares the reinforcing effects of the several fibers studied at 30 wt %. The data show that particular fibers improve particular properties. The tensile modulus and tensile strength are most improved by glass the heat deflection is most improved by asbestos, and the impact strength is most improved by polyester. 

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