Poly dielectric properties

Electrical Properties. AH polyolefins have low dielectric constants and can be used as insulators in particular, PMP has the lowest dielectric constant among all synthetic resins. As a result, PMP has excellent dielectric properties and alow dielectric loss factor, surpassing those of other polyolefin resins and polytetrafluoroethylene (Teflon). These properties remain nearly constant over a wide temperature range. The dielectric characteristics of poly(vinylcyclohexane) are especially attractive its dielectric loss remains constant between —180 and 160°C, which makes it a prospective high frequency dielectric material of high thermal stabiUty. 

Recently siloxane-imide copolymers have received specific attention due to various unique properties displayed by these materials which include fracture toughness, enhanced adhesion, improved dielectric properties, increased solubility, and excellent atomic oxygen resistance 1S3). The first report on the synthesis of poly(siloxane-imides) appeared in 1966, where PMDA (pyromellitic dianhydride) was reacted with an amine-terminated siloxane dimer and subsequently imidized 166>. Two years later, Greber 167) reported the synthesis of a series of poly(siloxane-imide) and poly(siloxane-ester-imide) copolymers using different siloxane backbones. However no physical characterization data were reported. 

Table I. Dielectric properties of UV and heat cured poly(4-allyloxystyrene)...

Table 3. Thermal and dielectric properties of poly(aminobisamleimides)...

PTC) is a family of polymers whose thermal properties, Tg, unperturbed dimensions and partial specific volumes has been reported [248-252], The dielectric properties of these polymers were recently studied [253-256], Relaxational studies on poly(thiocarbonate)s are scarce, but on the contrary there is much information about relaxation processes of the analogues poly(carbonate)s (PC). Therefore the study of PTC is an interesting approach to get confidence about the motions responsible of the relaxational behavior of these polymers. 

Fig. 23 a, b. Dielectric properties of polyelectrolyte complexes881 (a) Variation of dielectric constant e and loss factor e" of polyelectrolyte complexes with frequency (b) Variation of loss tangent e"/e of polyelectrolyte complexes with frequency. NaSS = poly(sodium styrenesulfonate), PAA = polyfacrylic add), PVBMA = poly(4-vinylbenzyl-trimethylammonium chloride), PEI = polyethyleneimine, lonene (Bubond 60) = — 2CTK... 

TABLE 1. Summary of physical and dielectric properties of selected poly(arylene ethers) prepared using the Ullmann ether catalyst. 

The mechanism of the polarity inversion of tautomeric molecules is totally different from the orientation polarization of conventional organic dielectrics, such as camphor and poly(vinylidene fluoride), and the dielectric response of this new type of dielectric should be much faster. Furthermore, a significant contribution of the proton-tunnelling mechanism to the proton tautomerism is frequently observed. Consequently, the dielectric property derived from proton tautomerization should have a high chance of being related to quantum phenomena. 

Figure 18.18 Map of dielectric properties of engineering plastics. Among engineering plastics, SPS (impact modified and GF-reinforced HB and IR grades) has very low dielectric dissipation factor and dielectric constant following those of fluorocarbon polymers. PSF, polysulfone PPE, poly(phenylene ether) PES, poly(ether sulfone) PAr, polyarylate...

Polymers such as poly(ethyleneglycol) also serve to dehydrate proteins in solution as do salts, and they alter somewhat the dielectric properties in a manner similar to organic... 

Ordered polymer films made from poly benzthiazole (PBZT) and poly benzoxazole (PBO) can be used as substrates for multilayer printed circuit boards and advanced interconnects to fill the current need for high speed, high density packaging. Foster-Miller, Inc. has made thin substrates (0.002 in.) using biaxially oriented liquid crystal polymer films processed from nematic solutions. PBZT films were processed and laminated to make a substrate with dielectric constant of 2.8 at 1 MHz, and a controllable CTE of 3 to 7 ppm/°C. The films were evaluated for use in multilayer boards (MLBs) which require thin interconnect substrates with uniform controllable coefficient of thermal expansion (CTE), excellent dielectric properties, low moisture absorption, high temperature capability, and simple reliable processing methods. We found that ordered polymer films surpass the limitations of fiber reinforced resins and meet the requirements of future chip-to-chip interconnection. 

Minakata A, Imai N, Oosawa F. Dielectric properties of poly electrolytes. II. A theory of dielectric increment due to ion fluctuation by a matrix method. Biopolymers 1972 11 347-359. 

Mandel M, Odijk T. Dielectric properties of poly electrolyte solutions. Ann Rev... 

Muller G, van der Touw F, Zwolle S, Mandel M. Dielectric properties of poly-L-glutamic acid in salt free aqueous solutions. Biophys Chem 1974 2 242-254. 

Warashina A, Minakata A. Dielectric properties of poly electrolytes. IV. Calculation of dielectric dispersion by a stochastic model. J Chem Phys 1973 58 4743-4751. 

Dielectric measurements on poly(vinyl acetate) were obtained utilizing a Fourier transform dielectric spectrometer developed in our laboratory (6). A voltage step pulse was applied to the sample and the time dependent Integrated current response, Q(t), was collected by computer. The frequency dependent dielectric properties, e and e" were then obtained from the Fourier trans-... 

R. Tu and T. Goto, Dielectric properties of poly- and single-crystalline BaTi20s, Mater. Trans., 47, 2898-2903 (2006). 

Ferroelectric composites are alternatives to standard piezoelectric and pyroelectric ceramics such as lead zirconate titanate (PZT) and BaHOs (BT). They combine the strong ferroelectric and dielectric properties of ceramics with the easy processing and good mechanical properties of polymers. Dispersion of micrometer-sized ferroelectric particles in an electrically passive epoxy matrix was first published by Furukawa et al. [1976] and later extended to ferroelectric matrices such as poly(vinylidene fluoride) (PVDF) and poly(vinylidene fluoride-co-3-fluoroethylene) (PVDF-TrFE) [Hsiang et al., 2001 Hilczer et al., 2002 Gimenes et al., 2004 Lam et al., 2005 Beloti et al., 2006]. However, the necessity of miniaturization of electronic components and... 

Some substimted diacetylenes (R-C=C-CMI -R, hereinafter referred to as DA) constitute a class of crystals polymerizable in the solid state [1]. One may thus obtain large single crystals, built of poly diacetylene (PDA) chains parallel to one another. A pronounced anisotropy of the systems, due to the presence of long TC-conjugated chains, resulted in an interest concerning electrical and opticd properties of DA [2,3]. Much less attention has been paid to studies of their dielectric properties [4-6]. 

A. R. A. Schettini, D. Khastgir, B. G. Soares, Microwave Dielectric Properties and EMI Shielding Effectiveness of Poly(Styrene-B-Styrene-Butadiene-Styrene) Copolymer Filled with PAni.Dodecylbenzenesulfonic Acid and Carbon Black. Polym. Eng. Sci. 2012, 52, 2041-2048. 

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