Binder electrical properties

Phenol—formaldehyde resins are used as mol ding compounds (see Phenolic resins). Their thermal and electrical properties allow use in electrical, automotive, and kitchen parts. Other uses for phenol—formaldehyde resins include phenoHc foam insulation, foundry mold binders, decorative and industrial laminates, and binders for insulating materials. 

Nylon Cloth Grade with Phenolic Resin Binder. Grade N-1 has excellent electrical properties under high humidity conditions and good impact strength, but is subject to flow or creep under load, especially at temperatures higher than normal. 

Carbon microspheres yield syntactic foams with resistivities that are astonishingly low for these materials. Novolac syntactic foams with carbon microspheres have resistivities of 0.02-0.5 Ohm m (depending on the filler concentration)77 this is ten orders of magnitude lower than for glass microspheres in the same binder For materials made from carbon microspheres and silicone rubbers, the resistivity depends exponentially on the temperature, viz. 0.08 Ohm m at 20 °C, 0.2 Ohm m at 60 °C, and 200 Ohm m at 95 °C 1). Consequently, carbon microspheres make it possible to produce syntactic foams with electric properties appropriate for semiconductors. 

Hydroxyl-terminated polydiene resins gelled by the reaction with orthosilicate esters have increased thermal stability. These polymeric gels, like silicone rubbers, exhibit outstanding electrical properties. The polymeric gels crosslinked at ambient temperature are castable as self-curing liquids. For example, they are used as binders for rocket solid fuels, in coatings for pipes, tanks, etc. They can be mixed with rubbers. 

The electrical properties of a series of eight different tank coating systems in contact with respectively seawater, crude oil and kerosine were determined [2], as a part of a tank coatings research program. The results measured for one of these coatings, an epoxy coal-tar system cured with an amine adduct (26 %wt. binder, 35 %wt. coal-tar and 39 %wt. talc/ barytes pigments) are reported in this chapter. 

One of the main differences of electrodeposition paints with conventional water soluble paints is their lower solids and thus solvent content. A typical binder content is around 10%w, the amount of solvent approximately 5%. The rest, apart from pigmentation, is water. The influence of solvent in the early stages of binder/paint formulation is very similar to the effects described for conventional aqueous paints which is also started from an approx. 70% solids binder solution in coupling solvent(s). The choice of the solvent (blend) is, however, less influenced by its evaporation characteristics as the deposited paint film does not contain much water and is stoved after application. Of more importance are paint stability and electrical properties (conductivity, rupture voltage). 

Chen ZH, Christensen L, Dahn JR (2004) Mechanical and electrical properties of poly (vinylidene fluoride-tetrafiuoroethylene-propylene)/super-S carbon black swelled in liquid solvent as an electrode binder for lithium-ion batteries. J Appl Polym Sci 91 2958-2965... 

Although both thermosetting resins and thermoplastic polymers are nsed as binders in laminates, the thermosetting materials are more conunon becanse they generally provide superior stability, thermal resistance, and electrical properties. 

Grade G-7 (glass fabric with silicon resin binder) This material has excellent heat resistance and arc resistance. It resists burning and has good electrical properties. Its physical properties are excellent. 

Grade G-9 (glass fabric with moisture-resistant melamine resin binder) This material retains its electrical properties better than class G-5 under wet conditions. Other characteristics are similar to G-5. Rods and tubes are available. 

Grade G-10 (glass fabric with epoxy resin binder) Laminates of G-10 have very high mechanical strengths at room temperature. Electrical properties are also very good. Rods and rolled tubes are available. 

As already stated, the addition of metallic fillers to a formulation serves to decrease the electrical insulation, but there may be other effects on the compound s electrical properties that may need to be taken into account. The frequency dependence of the dielectric loss factor increases as the metallic particles offset the low loss factors of the binder system. The loss factor is defined as the product of the power factor and the dielectric constant and is a measure of the signal absorption by the compound. Normally, low loss factors are desirable, particularly where a material is to be used in devices operating at high speed such as gallium arsenide based semiconductors, and this should be taken into account when formulating with conductive extenders. 

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