Loss shear modulus

Fig. 4. Temperature dependence of the shear loss modulus of poly(methyl methacrylate) (1), poly(n-propyl methacrylate) (2), poly(2-hydroxyethyl methacrylate) (3), poly(5-hydroxy-3-oxapen-tyl methacrylate) (4), and poly(8-hydroxy-3,6-dioxaoctyl methacrylate) (5)...

Fig. 5. Temperature dependence of the shear loss modulus of poly(pivaloyl-2-oxyethyl methacrylate) atactic (—), isotactic (---)...

Fig. 12. Effect of the volume fraction of methacrylic acid on the temperature dependence of the shear loss modulus of copolymers with 2-hydroxyethyl methacrylate 1 = 0.00 2 = 0.14 3 = 0.39 4 = 0.72 5 = 1.00...

Estimate the maximum shear loss modulus for a sample with 70% crystallinity. 

By assuming a linear variation of the crystallinity with the maximum of the shear loss modulus for the y and a mechanical relaxations, a simple linear interpolation leads to... 

FIGURE 10.14 Fracture energy, G, versus shear loss modulus, G", for six unfilled amorphous elastomers. (From Mullins (1959).)... 

Pakalapati et al [115] investigated some carbon/thermoplastic laminates. The materials were pultruded and they consisted of 50 v/o unidirectional continuous polyacrylonitrile-based carbon fibres in DuPont J-2 aromatic polyamide-based thermoplastic matrix. They were subjected to anodic and cathodic currents in sea water. Dynamic mechanical analysis was carried out in situ to measure the shear storage modulus (G ) and shear loss modulus (G") of 1.27mm diameter rod shaped samples, subjected to small amplitude torsional oscillations. The moduli were constant with time in air. 

Tensile loss modulus, shear loss modulus and tan 8 values are obtained from the damping signal, again using instrument correction factors. 

Shear relaxation modulus Shear stress relaxation modulus Shear loss modulus Complex shear modulus Enthalpy Henry... 

Fig. 15. Temperature dependencies of shear loss modulus for PCL-PVC blends, showing the secondary relaxations, curves shifted for clarity data taken from [2]...

The quantities G and G" are the shear storage modulus and the shear loss modulus, respectively. G is a measure of the average amount of energy stored in the sample during a period of the oscillation while G" is a measure of the amount of energy lost as heat during the same period. This entire derivation is completely analogous to that for loss in an RC circuit in electronics or for a driven harmonic oscillator in simple mechanical systems. It is also possible to express Eq. (19) as Eq. (20),... 

Figure 7. Shear storage modulus, G and shear loss modulus, G", as a function of temperature for a monolithic specimen of epoxy-based structural adhesive cured at 120°C.

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