Dissipation factor frequency

In air, PTFE has a damage threshold of 200—700 Gy (2 x 10 — 7 x 10 rad) and retains 50% of initial tensile strength after a dose of 10" Gy (1 Mrad), 40% of initial tensile strength after a dose of 10 Gy (10 lad), and ultimate elongation of 100% or more for doses up to 2—5 kGy (2 X 10 — 5 X 10 rad). During irradiation, resistivity decreases, whereas the dielectric constant and the dissipation factor increase. After irradiation, these properties tend to return to their preexposure values. Dielectric properties at high frequency are less sensitive to radiation than are properties at low frequency. Radiation has veryHtde effect on dielectric strength (86). 

The dissipation factor (the ratio of the energy dissipated to the energy stored per cycle) is affected by the frequency, temperature, crystallinity, and void content of the fabricated stmcture. At certain temperatures and frequencies, the crystalline and amorphous regions become resonant. Because of the molecular vibrations, appHed electrical energy is lost by internal friction within the polymer which results in an increase in the dissipation factor. The dissipation factor peaks for these resins correspond to well-defined transitions, but the magnitude of the variation is minor as compared to other polymers. The low temperature transition at —97° C causes the only meaningful dissipation factor peak. The dissipation factor has a maximum of 10 —10 Hz at RT at high crystallinity (93%) the peak at 10 —10 Hz is absent. 

To minimize electrical losses, especially at high frequencies, a low dissipation factor is required. High volume resistance provides good insulation to prevent... 

Electrical Properties. Polysulfones offer excellent electrical insulative capabiUties and other electrical properties as can be seen from the data in Table 7. The resins exhibit low dielectric constants and dissipation factors even in the GH2 (microwave) frequency range. This performance is retained over a wide temperature range and has permitted appHcations such as printed wiring board substrates, electronic connectors, lighting sockets, business machine components, and automotive fuse housings, to name a few. The desirable electrical properties along with the inherent flame retardancy of polysulfones make these polymers prime candidates in many high temperature electrical and electronic appHcations. 

The electneal properties of PTFE are dominated by its extremely tow dielectric constant (2.1) This value is invanant over a broad range ot temperatures (- 40 to 250 °C) and frequencies (5 Hzto 10 GHz). Smularly, PTFE has an unusually low dissipation factor, which is also quite mdependent of temperature and frequency fhis behavior results from the high degree of dipolar symmetry of the perfluonnated and unbranched chains The dielectnc strength, resistivity, and arc resistance are very high... 

Dissipation Factor at Frequency of 10 Hz 30. Solubility-Soluble in CCL, ether, ethanol and most organic solvents (3) —21DC 0.0011... 

The dissipation factor of a polymer (which we also refer to as tan 5) is the ratio of energy lost to the energy stored when it is placed in an alternating field. The dissipation factor is analogous to a mechanical tan 8 describing rheological behavior. The dissipation factor at a specific frequency is defined according to Eq. 8.14. 

Rodahl M, Hook F, Fredriksson C, Keller CA, Krozer A, Brzezinski P, Voinova M, Kasemo B (1997) Simultaneous frequency and dissipation factor QCM measurements of biomolecular adsorption and cell adhesion. Faraday Discuss 107 229-246... 

IEC 60250, Recommended methods for the determination of the permittivity and dielectric dissipation factor of electrical insulating materials at power, audio and radio frequencies including metre wavelengths, 1969. 

The dissipation factor of capacitors at high frequencies is determined by the series resistance. For low frequencies there may be losses caused by leakage currents as well as by slow components in the polarizability, especially of high e ceramics and polymer dielectrics. The dissipation factor of the SIKO at room temperature is below 10-4. At 200 °C it is still very low (2X10-4). 

Material response is typically studied using either direct (constant) applied voltage (DC) or alternating applied voltage (AC). The AC response as a function of frequency is characteristic of a material. In the future, such electric spectra may be used as a product identification tool, much like IR spectroscopy. Factors such as current strength, duration of measurement, specimen shape, temperature, and applied pressure affect the electric responses of materials. The response may be delayed because of a number of factors including the interaction between polymer chains, the presence within the chain of specific molecular groupings, and effects related to interactions in the specific atoms themselves. A number of properties, such as relaxation time, power loss, dissipation factor, and power factor are measures of this lag. The movement of dipoles (related to the dipole polarization (P) within a polymer can be divided into two types an orientation polarization (P ) and a dislocation or induced polarization. 

The electrical properties of materials are important for many of the higher technology applications. Measurements can be made using AC and/or DC. The electrical properties are dependent on voltage and frequency. Important electrical properties include dielectric loss, loss factor, dielectric constant, conductivity, relaxation time, induced dipole moment, electrical resistance, power loss, dissipation factor, and electrical breakdown. Electrical properties are related to polymer structure. Most organic polymers are nonconductors, but some are conductors. 

The power factor (dissipation factor) is the energy required to rotate the dipoles of a polymer in an applied electrostatic field of increasing frequency (ASTM-D150). The loss factor is equal to the product of the power factor and the dielectric constant of the polymer. 

The electric properties of a material vary with the frequency of the applied current. The response of a polymer to an applied current is delayed because of a number of factors including the interaction between polymer chains, the presence within the chain of specific molecular groupings, and effects related to interactions within the specific atoms themselves. A number of parameters are employed as measures of this lag, such as relaxation time, power loss, dissipation factor, and power factor. 

Relative to microelectronic applications, the out-of-plane dielectric constant for BPDA-PFMB films measmed after aging at 50% relative humidity for 48 h at 23°C was between 2.8 and 2.9 (0.1 kHz to 1 MHz) (ASTM D-150-81These values are considerably lower than that of commercial polyimides such as PMDA-ODA (pyromellitic dianhydride, PMDA) (s = 3.5 at 1 kHz and 3.3 at 10 MHz). The dielectric constant and tan 8 (dissipation factor) were temperature- and frequency-dependent. The dielectric constant, which was independent of temperature until near 210°C increased above this point until a frequency-dependent maximum was reached at about 290°C. The dissipation factor, which was also independent of temperatme below 200°C, underwent a rapid increase with no maximum between 200 and 400°C owing to ion conductivity. The temperatme at which this increase occurred increased as the frequency increased. The films also... 

Figure 1. Dissipation factor vs. logarithm of frequency at various hydration levels. A NaF86.5 at 12°C. B NaF54.7 at 12°C...

Lossy Transmission Lines. For lossy transmission lines, the conductor resistance, fl, and dielectric conductance, G, must be considered. The assumption G a)C is usually valid, because the dissipation factor, tan 8 = G/wC, is usually less than 0.01 for most packaging dielectrics (although the dissipation factor may become larger at very high frequencies). For high... 

The standard method for making measurements of dielectric properties is to place a sample between closely spaced parallel conducting plates, and to monitor the AC equivalent capacitance and dissipation factor of the resulting capacitor. The capacitance is proportional to the dielectric permittivity (e ) at the measurement frequency, and the dissipation factor in combination with the value can be used to extract the dielectric loss factor (e"). ... 

The dielectric constant remains at 2.04 over a wide range of temperature and frequencies (from 100 Hz to 1 GHz). The dissipation factor at low frequencies (from 10 Hz to 10 kHz) decreases with increasing frequency and decreasing temperature. In the range from 10 kHz to 1 MHz, temperature and frequency have little effect while above 1 MHz the dissipation factor increases with the frequency.55... 

ETFE exhibits excellent dielectric properties. Its dielectric constant is low and essentially independent of frequency. The dissipation factor is low, but increases... 

Class II/III dielectrics consist of high-permittivity ceramics based on ferro-electrics. They have er values between 2000 and 20 000 and properties that vary more with temperature, field strength and frequency than Class I dielectrics. Their dissipation factors are generally below 0.03 but may exceed this level in some temperature ranges and in many cases become much higher when high a.c. fields are applied. Their main value lies in their high volumetric efficiency (see Table 5.1). 

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