Hydrocarbon, dielectric loss

Dielectric Loss. Usually, the dielectric loss of plasma polymerized hydrocarbon is larger than that of the conventional polymer by more than one order of magnitude. This difference is supposed to be caused by the oxidation of the film (J34). For both samples of PPE, a loss peak appeared at -30 °C at the measurement frequency of 1 KHz. The activation energy of this peak was 0.68 eV as shown in Fig. 8 for both samples. This value was almost same as... 

The observation of these dielectric relaxation processes arising from carbonyl features, has also been reported by Tibbit and co-workers in plasma polytetra-fluoroethylene as well as other plama polymers. In measuring the dielectric loss tangents over a frequency range of 10 -10 Hz at temperatures of — 150 to 100 °C, they have demonstrated that the dielectric loss curves of plasma polymers derived from hydrocarbon and fluorocarbon monomers are very similar, but bear no resemblence to their conventionally polymerized counterparts. 

Electrical Properties JSR RB has similar electrical properties to polyethylene with the exception of dielectric loss tangent and since it is a hydrocarbon, it possesses better insulating properties than plasticized PVC.Oi l... 

There appears little prospect of producing a noncrystalline pol3rmer with a dipolar monomer unit and a dielectric loss factor below 10 Hydrocarbon pol3nners with optimised mechanical properties and suitable antioxidants look much more promising. 

Dielectric Loss (Dfor Tan 5). The energy absorbed by the dielectric media is called dielectric loss. Attenuation is proportional to tan 5 and signal frequency. For standard FR-4 ML-PWB materials, tan 5 is 0.02, which translates into serious losses at frequencies above 1 GHz. For circuits operating above 1 GHz, a lower loss material is required.There are a number of material choices for lower dielectric attenuation, including blended epoxies, hydrocarbon ceramic, polytetrafluoroethylene (PTFE), and PTFE with ceramic. The tan d values of these materials are approximately. 01,. 004,. 002, and. 001, respectively. 

These plastics exhibit low dielectric losses and stable dielectric constants over a broad range of temperatures and frequencies. The chemical resistance of the materials is their weakest point. Although resistant to most common solvents, acids and alkalis, they exhibit stress cracking in the presence of organic ketones, esters and chlorinated hydrocarbons. Polysulphones are used in the electronics field for connectors, chip carriers and capacitor dielectrics, and they are the first of the high temperature thermoplastics to be used for printed wiring board fabrication. 

A particular application, the marine battery lid, is treated in greater detail below. Propylene-based plastics exhibit the chemical inertness associated with paraffin hydrocarbons, of which class they are high-molecular-weight members this allows their use in contact with a wide variety of liquids, both domestic and industrial. In view of their structure, propylene polymers have excellent electrical properties, including very low dielectric losses. 

For many years the petroleum industry has defined nonconductive liquids as having conductivities less than 50 pS/m. A higher value of 100 pS/m is used here to address the higher dielectric constants of certain flammable chemicals in relation to petroleum products. For example the dielectric constant of ethyl ether is 4.6 versus 2.3 for benzene from Eq. (2-3.2), ethyl ether therefore has the same relaxation time at a conductivity of 100 pS/m as benzene at a conductivity of 50 pS/m. It is the relaxation time, not the conductivity alone, that determines the rate of loss of charge hence the same logic that makes 50 pS/m appropriate for identifying nonconductive hydrocarbons makes 100 pS/m appropriate for identifying nonconductive chemical products. 

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