Electrical properties, polymers

Light emitting diodes. 2. Polymers—Electric properties. 3. Electroluminescent devices—Materials. I. Li, Zhigang R., 1958- II. Meng, Hong, 1966- III. Optical science and engineering (Boca Raton, Fla.) 110. 

D.H. Kim, S.M. Richardson-Bums, J.L. Hendricks, C. Sequera, and D.C. Martin, Effect of immobilized nerve growth factor on conductive polymers Electrical properties and cellular response, Adv. Fund. Mater., 17(1), 1-8 (2006). 

Photonics— Materials—Congresses. 2. Polymers—Optical properties— Congresses. 3. Optoelectronic devices— Materials—Congresses. 4. Polymers— Electric properties—Congresses. 

Polymers-Electric properties. 2. Polymers-Optical properties. I. Wise, Donald L. (Donald Lee). II. Series Plastics engineering (Marcel Dekker, Inc.) 45. 

Table 9.10 shows some key polymer electrical property data taken from the compilation of Ku and Liepens [41] with the exception of the PMTFPS data reported in [8]. 

Polymers— Electric properties congresses. 2. Organic semiconductors Congresses. 

Kim DH, Sequerah C, Hendricks JL et al (2007) Effect of immobilized nerve growth factor (NGF) on conductive polymers electrical properties and cellular response. Adv Fund Mater 17 79-86... 

Subjects LCSH Conjugated polymers. Polymers—Electric properties. ... 

A VinylcarbaZole. Vinylation of carba2ole proceeds in high yields with alkaline catalysts (212,213). The product, 9-ethenylcarba2ole, [1484-13-5] forms rigid high-melting polymers with outstanding electrical properties. 

Some electrical properties are shown in Table 3. Values of other parameters have been pubflshed (146). Polymorphism of the PVDF chains and the orientation of the two distinct dipole groups, —CF2— and —CH2—, rather than trapped space charges (147) contribute to the exceptional dielectric properties and the extraordinarily large piezoelectric and pyroelectric activity of the polymer (146,148,149). 

PCTFE exhibits very good electrical properties ia terms of high iasulation resistance, minimal trackiag, corona formation, and surface flashover due to the polymer s nonwettable surface and ultralow moisture absorption (Table 3). 

R. E. Schawmm, A. E. Clark, and R. P. Reed,M Compilation and Evaluation of Mechanical, Thermal and Electrical Properties of Selected Polymers, NBS Report, A EC SAN-70-113, SANL 807 Task 7, SANL Task 6, National Technical Information Service, U.S. Dept, of Commerce, Springfield, Va., Sept. 1973, pp. 335-443. 

Electrical Properties. CeUular polymers have two important electrical appHcations (22). One takes advantage of the combination of inherent toughness and moisture resistance of polymers along with the decreased dielectric constant and dissipation factor of the foamed state to use ceUular polymers as electrical-wire insulation (97). The other combines the low dissipation factor and the rigidity of plastic foams in the constmction of radar domes. Polyurethane foams have been used as high voltage electrical insulation (213). 

Electrical Insulation. The substitution of a gas for part of a soHd polymer usuaUy results in large changes in the electrical properties of the resulting material. The dielectric constant, dissipation factor, and dielectric strength are aU generaUy lowered in amounts roughly proportional to the amount of gas in the foam. 

Plasma-deposited siUcon nitride contains large amounts of hydrogen, typically in the range of 20—25 atomic % H, and has polymer-like properties. The electrical resistivity of the film depends on the deposition temperature, the film stoichiometry, and the amounts of hydrogen and oxygen in the film. 

Electrical Properties. Erom a chemical standpoint, HDPE is a saturated aUphatic hydrocarbon and hence a good insulator. Its electrical characteristics are given in Table 1. Because polymer density and molecular weight affect electrical properties only slightly, HDPE is widely used for wire and cable insulation. 

Sihcones (qv) have an advantage over organic resias ia their superior thermal stabiUty and low dielectric constants. Polyurethanes, when cured, are tough and possess outstanding abrasion and thermal shock resistance. They also have favorable electrical properties and good adhesion to most surfaces. However, polyurethanes are extremely sensitive to and can degrade after prolonged contact with moisture as a result, they are not as commonly used as epoxies and sihcones (see Urethane polymers). 

Automotive appHcations account for about 116,000 t of woddwide consumption aimuaHy, with appHcations for various components including headlamp assembHes, interior instmment panels, bumpers, etc. Many automotive appHcations use blends of polycarbonate with acrylonitrile—butadiene—styrene (ABS) or with poly(butylene terephthalate) (PBT) (see Acrylonitrile polymers). Both large and smaH appHances also account for large markets for polycarbonate. Consumption is about 54,000 t aimuaHy. Polycarbonate is attractive to use in light appHances, including houseware items and power tools, because of its heat resistance and good electrical properties, combined with superior impact resistance. 

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