Dielectric polymers, applications

As previously noted, the dielectric constant, e (ASTM D-150-74), is the ratio of the capacity of a condenser made with or containing the test material compared with the capacity of the same condenser with air as the dielectric. Polymers employed as insulators in electrical applications should have low dielectric constants, while those used as semiconductors or conductors should have high dielectric constants. 

Avatrel Dielectric Polymers (low-k dielectric applications such as interlayer dielectrics, passivation layers, die attach adhesives, chip encapsulants (both molding and adhesive) and underfill materials). 

B. F. Goodrich, along with Georgia Institute of Technolog/s Packaging Research Center, have been developing cyclic olefin-based Avatrel dielectric polymers that exhibit many of the key performance criteria required for this demanding application. They include ... 

J. Mijovic and B. D. Fitz, Dielectric Spectroscopy of Reactive Polymers, Application Note Dielectrics 2, Novocontrol GmbH, 1998. 

Thermally stimulated depolarization (TSD), e.g. [101]. TSD is applicable to dielectric polymers that are electrets. Depolarization currents are monitored and these currents are related to the relaxation of electric charges in the sample as a function of the number of events that take place in the sample at the molecular and supermolecular level. 

MoBinger H (2010) Demonstrating the application of dielectric polymer actuators for tactile feedback in a mobile consumer device. Master thesis technische Universitat Darmstadt, Darmstadt... 

The historical interest in the electrical properties of polymers revolved aroimd their insulating and low dielectric properties. The vast majority of polymer applications involving electrical properties relies on their insulating characteristics, such as with wire and cable insulation as well as general apphance utility where insulating housings are desired. The dielectric properties of polymer blends has been covered earlier as a valuable method for characterization... 

This eapability for prediction of polymeric crystals was developed only quite reeendy. So far, we have systematically studied ten common polymers. And this module has heen used for the design of dielectric polymers. Here we illustrate the application to predict two complex polymers, nylon-6 and cellulose. 

Finally, the dielectric properties of a nonpolar polymer are modified by inclusion of even small amounts of a polar comonomer. In coatings applications the presence of polar repeat units in an otherwise nonpolar polymer reduces the tendency for static buildup during manufacture, printing, and ultimate use. On the other hand, in dielectric applications this increases the power loss and must be kept to a minimum, even to the exclusion of polar initiator fragments. 

Where plastics are to be used for electrical applications, then electrical properties as well as mechanical and other properties need to be considered. Whilst properties such as resistivity, power factor and dielectric constant are important, they may not be all-important. For example, although polyamides and many thermosetting plastics may show only moderate values for the above properties, they have frequently been used successfully in low-frequency applications. Perhaps more important for many purposes are the tracking and arcing resistance, which are frequently poor with aromatic polymers. 

In conclusion RAIRS, which affords high spectral resolution, is a very versatile nondestructive optical technique which does not depend on a vacuum environment. Vibrational spectra also serve as characteristic fingerprints for adsorbate molecules, adsorption configurations, and structures on metallic and dielectric substrates. Extension to include dielectric substrates opened new fields of application in polymer and biochemical research. 

Abstract Current microwave-assisted protocols for reaction on solid-phase and soluble supports are critically reviewed. The compatibility of commercially available polymer supports with the relatively harsh conditions of microwave heating and the possibilities for reaction monitoring are discussed. Instrmnentation available for microwave-assisted solid-phase chemistry is presented. This review also summarizes the recent applications of controlled microwave heating to sohd-phase and SPOT-chemistry, as well as to synthesis on soluble polymers, fluorous phases and functional ionic liquid supports. The presented examples indicate that the combination of microwave dielectric heating with solid- or soluble-polymer supported chemistry techniques provides significant enhancements both at the level of reaction rate and ease of purification compared to conventional procedures. 

Source Liu, C. et at, Electro-statically stricted polymers (ESSP), SPIE Conference on Electroactive Polymer Actuator and Devices, Newport Beach, California, March 1999, SPIE Vol. 3669,0277-786X/99 Kombluh, R. et at, Application of Dielectric Elastomer EAP Actuators, SPIE— the International Society for Optical Engineering, Bellingham, Washington, 2001, Chapter 16. 

Pelrine, R., Sommer-Larsen, P., Kombluh, R., Heydt, R., Kofod, G., Pei, Q., and Gravesen, P., Applications of dielectric elastomer actuators, in SPIE, smart stmctures and materials, 2001, Electroactive polymer actuators and devices, Y. Bar-Cohen (Ed.), Proceedings of SPIE, Vol. 4329, 0277-786X/2001. 

Prahlad, H., Kombluh, R., Pelrine, R., Stanford, S., Eckerle, J., and Oh, S. Polymer power Dielectric elastomers and their applications in distributed actuation and power generation. Proceedings of ISSS International Conference on Smart Materials, Structures and Systems, Bangalore, India, July 28-30, 2005, SA-13, pp. 100-107. 

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