Electrical properties fibres

Glass fibre reinforced PSU/PBT alloys offer good electrical properties combined with high heat deflection temperatures and a VO classification in the UL94 fire rating. 

Metal fibre mat Electrical property RF shielding Overmoulding... 

The fact that the majority of in vivo processes occur on the surface of or within the membrane and that electrical phenomena are very important in membranes such as those found in the chloroplast, muscle fibres, nerve fibres, mitochondria, etc., has recently led to intensive study of the electrical properties of bilayer lipid membranes (BLM) in an attempt to reproduce a model of the cell membrane. Membranes of 5-10 nm thickness have been studied, the membranes consisting of two parallel sheets of lipids with a hydrophobic environment in the interior of the membrane and the hydrophilic groups directed to the exterior aqueous medium. 

Eddy current (EC) Inspection of carbon fibre-reinforced structures bases on their anisotropic electrical properties. Great differences in conductivity between carbon fibres, polymer matrix and integrated functional components contribute to this circumstance. The paper describes suitable eddy current probes, the fundamental idea of modelling and measurement of EC distribution and provides a short survey of application potential to characterise CFRP non-destructively. 

Nearly every polymeric system absorbs some moisture under normal atmospheric conditions from the air. This can be a difficult to detect, very small amount as for polyethylene or a few percent as measured for nylons. The sensitivity for moisture increases if a polymer is used in a composite system i.e. as a polymeric matrix with filler particles or fibres dispersed in it. Hater absorption can occur then into the interfacial regions of filler/fibre and matrix [19]. Certain polymeric systems, like coatings and cable insulation, are for longer or shorter periods immersed in water during application. After water absorption, the dielectric constant of polymers will increase due to the relative high dielectric constant of water (80). The dielectric losses will also increase while the volume resistivity decreases due to absorbed moisture. Thus, the water sensitivity of a polymer is an important product parameter in connection with the polymer s electrical properties. The mechanical properties of polymers are like the electrical properties influenced by absorption of moisture. The water sensitivity of a polymer is therefore in Chapter 7 indicated as one of the key-parameters of a polymeric system. 

For 2D anisotropy, iron or Fe N plates or plane hexagonal ferrite disposed in parallel plans can be used. For ID anisotropy, micronic iron fibres oriented in different directions may be used. Far more complicated than conventional materials, their radio-electrical properties in the three directions must be determined. 

M. Granstrom and O. Inganas, Electrically conductive polymer fibres with mesoscopic diameters 1. Studies of structure and electrical properties. Polymer, 36, 2867-2872... 

Chand, N. Jain, D. (2005). Effect of Sisal Fibre Orientation on Electrical Properties of Sisal Fibre Reinforced Epoxy Composites. Composites Part A, Vol.36, No.5, (May 2005),... 

B. Fankhanel, E. Muller, U. Mosler, W. Siegel and W. Beier, Electrical Properties and Damage Monitoring of SiC-Fibre-Reinforced Glasses, Comp. Sci. Technol. 61, 825-830 (2001). 

Foly(ethylene terephthalate) (PET). A microcrystalline thermoplastic polyester. As a man-made fibre, it is suitable for producing clothing, domestic textiles, and industrial fabrics. PET films are excellent packaging and electrical insulating ma-terials with high mechanical strength, thermal stability, low vapour and gas permeability, favourable electric properties. PET moulding compounds are processed into... 

Molecular mass also has a significant effect on the rheological and electrical properties, such as viscosity, surface tension, conductivity and dielectric strength. It has been reported that polymers whose molecular mass is too low tend to form beads rather than fibres, while high molecular mass polymers give fibres with larger average diameter. 

Electrical properties such as conductivity, resistivity, I (current)-V (voltage) characteristics of vegetable oil-based polyurethane nanocomposites are sometimes influenced by nanocomposite formation with a suitable nanomaterial. BaTiOs superfine fibre-filled castor oil-modified polyure-thane/poly(methyl methacrylate) interpenetrating polymer network nanocomposites exhibit an increase in conductivity between insulator and semiconductor with an increase in nanofibre loading. ... 

Figure 4.10a presents an optical micrograph of the fibrous nanocomposite product, which shows the formation of continuous oriented nanofibres of about 200 nm diameter (Figure 4.10b). This yielded anisotropic electrical properties for the fibrous nanocomposite product, with an electrical conductivity of about 400 times higher in the direction of fibre orientation compared to the in-plane direction perpendicular to the fibres.

Electrical properties Glass fibre is nonconductive and is an ideal choice for electrical insulation, where designers ean make use of the high dielectric strength and low dieleetrie loss properties. 

Okubo A, Miyayama M, Yanagida H, Electrical properties of pitch based semi-conductive carbon fibres, J Ceramic Soc Japan, 103(9), 954-959, 1995. 

Shui ZH, Li JZ, Huang FP, Yang DP, Study on the electrical properties of carbon fibre cement... 

Besides mechanical properties, fillers change the optical and electrical properties, chemical and weathering resistance, flammability and density of polymers. In particular, most fillers destroy optical translucency, unless their refractive index (see Table 4.4) is the same as that of the polymer. Close agreement between the fibre and the polymer refractive index is required for translucency. Feldspar has a refractive index very similar to that of several polymers and so filled, translucent products can be obtained, but it is abrasive to processing equipment. 

Zhonghai and co-workers [154] studied the mechanical properties of carbon fibre reinforced films of this polymer as a function of the degree of crosslinking with triethylenetetramine. In general, an improvement in mechanical properties resulted in little or no effect on the electrical properties of this polymer, which is a strong candidate for the fabrication of lithium battery electrodes. 

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