Tangent delta tan

Quantitatively, lower dissipation factors result in higher-quality, higher-performance electrical or electronic systems, having lower electrical losses. Dissipation factor values have no units because they are mathematical ratios. Low dissipation factor values, desirable for electronic plastics, would be below 0.01 and 0.001. Two other terms for dissipation factor are loss tangent and tan delta. A related term is quality factor or Q factor, which is the reciprocal of the dissipation factor. See also dielectric properties electronic plastic. 

The measurement of the linear elastic properties is normally done through osciUatory measurements where strain, frequency, and temperature are controlled. If the material behaves perfectly elastically, then the stress recorded is in phase with the applied strain. If the material has no elasticity, but instead behaves perfectly viscously, then the recorded stress will be proportional to the strain rate, which is 90° out of phase with the applied strain, peaking where the strain is 0 in each sinusoidal cycle. Pressure-sensitive adhesives are viscoelastic materials and thus the recorded stress will peak in each cycle somewhere between 0° (in phase) and 90° (out of phase) with the applied strain. The tangent (sin/cos) of this phase angle 0 is a measure of the relative viscous to elastic contributions to the adhesive s stress response. When a material approaches its Tg tan delta (tan 6) increases. The temperature at... 

Figure 1 shows the 11 Hz modulus and loss tangent of monomer I cured for seven days at 280 C. (This was the standard cure cycle adopted during development of these resins). Three relaxation processes are evident as peaks in tan delta ... 

HLMI and melt viscosity at 100 s-1) were less affected. At higher diene concentration, the polymer became insoluble. These properties are characteristic of the presence of LCB. The tangent of delta is the ratio of the loss modulus divided by the storage modulus. Tan delta at 0.1 s 1 and the CY-a parameter dropped precipitously, which also indicates much greater elasticity in the polymer. 

Figure 3. Loss tangent (tan delta) vs. temperature for LiBr-PEUU 700 complexes at 11 Hz.

Tan Delta n Mathematically expressed as the loss modulus divided by the storage modulus, the tangent of the phase angle between an applied stress and the strain response in a dynamic experiment. NOTE - Tan delta versus temperature curves are commonly reported in dynamic mechanical analysis (DMA) tests. 

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