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Dissipation Factor (dissipation + factor)

Distribution by Scientific Domains

Polymers and Materials Science	100%

Selected Abstracts

Styrene 4-vinylbenzocyclobutene copolymer for microelectronic applications

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 8 2008
Ying-Hung So
Abstract Styrene and 4-vinylbenzocyclobutene (vinyl-BCB) random copolymers were prepared by free radical polymerization and studied for suitability as a dielectric material for microelectronic applications. The percentage of vinyl-BCB in the copolymer was varied from 0 to 26 mol % to optimize the physical and mechanical properties of the cured copolymer as well as the cost. Copolymer in which 22 mol % of vinyl-BCB was incorporated along with styrene produced a thermoset polymer which, after cure, did not show a Tg before decomposition at about 350 °C. The polymeric material has a very low dielectric constant, dissipation factor, and water uptake. The fracture toughness of the copolymer was improved with the addition of 20 wt % of a star-shaped polystyrene- block -polybutadiene. Blends of the poly(styrene- co -vinyl-BCB) with the thermoplastic elastomer provided material that maintained high Tg of the cured copolymer with only a slight decrease in thermal stability. The crosslinked styrenic polymer and toughened blends possess many properties that are desirable for high frequency-high speed mobile communication applications. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2799,2806, 2008 [source]

Structural and Electrical Properties of Er2O3 -Doped Na1/2Bi1/2TiO3 Lead-Free Piezoceramics

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2007
Mengjia Wu
Sodium bismuth titanates Na1/2Bi1/2TiO3 (NBT) doped with 0,3 wt% Er2O3 were prepared by the conventional solid-state reaction method. The X-ray diffraction results revealed that the sintered Er-doped NBT ceramics exhibited a pure perovskite structure with Er3+ concentrations ranging from 0 to 1 wt%. At a low Er2O3 concentration, the Er-doped NBT ceramics showed enhanced electrical properties with dielectric constant ,33T/,0=636, a low dielectric dissipation factor (tan ,=3.3%), a low coercive field (Ec=4.56 kV/mm), and a high piezoelectric constant (d33=75 pC/N). The relationship between the composition and properties of Er-doped NBT ceramics has been discussed. [source]

Influence of Ethylene Ionomers on the Electrical Properties of Crosslinked Polyethylene

MACROMOLECULAR MATERIALS & ENGINEERING, Issue 10 2006
Qing Quan Ke
Abstract Summary: Water treeing is a deterioration mechanism observed in the polymeric insulation of extruded cables, which can affect the service life of the transmission and distribution XLPE power cables. To improve the water-tree resistance of XLPE, it was blended with sodium-neutralized EAA-Na ionomers which were formed by neutralization of EAA with NaOH. A series of XLPE/EAA-Na ionomer blends were investigated for their electrical properties, such as water treeing, electrical breakdown strength, dielectric constant, and dissipation factor. The results strongly suggest that EAA-Na ionomers can improve the water-tree resistance of XLPE, and the XLPE/EAA-Na blends retain excellent dielectric properties. Characterization of XLPE/EAA-Na blends by using FTIR indicates that the neutralization reaction is effectively achieved. In addition, it can be found that XLPE/EAA-Na blends are partially compatible from observing morphology observations made by SEM and, therefore, EAA-Na ionomers can be well dispersed in the matrix. Water tree length of the XLPE/EAA-0.5Na blends. [source]

Dielectric Properties of a Printed Sol,Gel Matrix Composite,

ADVANCED ENGINEERING MATERIALS, Issue 5 2010
Tobias Lehnert
Low temperature processable materials with high dielectric constants are required for application on flexible organic substrates, for example, in printed electronics. To date, mainly organic polymers with embedded functional particles have been investigated for this purpose. For the first time, we present a printable dielectric composite material composed of ferroelectric high permittivity particles (BaTiO3) bonded by a mainly inorganic sol,gel derived network. The exemplary optimization of the properties by varying the sol,gel precursor illustrates the potential of sol,gel chemistry for printable functional materials. An operational gravure printed capacitor including printed silver electrodes is presented. The measured dielectric constants are among the highest reported in literature for low temperature cured films with moderate dissipation factors. Besides these promising dielectric properties, this composite film shows a ferroelectric response. [source]

Synthesis and physical properties of low-molecular-weight redistributed poly(2,6-dimethyl-1,4-phenylene oxide) for epoxy resin

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2008
Hann-Jang Hwang
Abstract Low-molecular-weight poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) was prepared by the redistribution of regular PPO with 4,4,-isopropylidenediphenol (bisphenol A) with benzoyl peroxide as an initiator in toluene. The redistributed PPO was characterized by proton nuclear magnetic resonance, mass spectra, and Fourier transform infrared spectroscopy. The redistributed PPO oligomers with terminal phenolic hydroxyl groups and low molecular weights (weight-average molecular weight = 800,4000) were used in the modification of a diglycidyl ether of bisphenol A/4,4,-diaminodiphenylmethane network system. The curing behaviors were investigated by differential scanning calorimetry and Fourier transform infrared spectroscopy. The effect of molecular weight and the amount of redistributed PPO oligomers incorporated into the network on the physical properties of the resulting systems were investigated. The thermal properties of the cured redistributed PPO/epoxy resins were studied by dynamic mechanical analysis, thermal mechanical analysis, thermogravimetric analysis, and dielectric analysis. These cured redistributed PPO/epoxy resins exhibited lower dielectric constants, dissipation factors, coefficients of thermal expansion, and moisture absorptions than those of the control diglycidyl ether of bisphenol A based epoxy. The effects of the composition on the glass-transition temperature and thermal stability are discussed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source]