Glass fibre electrical properties

For the electricity electronics markets. Table 2.18 displays the performances and costs of six engineering thermoplastics reinforced with glass fibres and UL94 VO rated. The designer can choose between four levels of costs, five levels of water absorption and several levels of mechanical and thermal properties according to the requirements. 

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. 

A special property of glass is that it can be drawn into fine fibres when it is in plastic state. Glass fibres combine the properties of fibres (they can be woven into cloth) with the properties of glass (they are bad conductors of heat and electricity). 

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). 

E-glass has a low alkali composition which produces the excellent electrical insulation properties and is the most commonly used glass fibre in FRP owing to its good mechanical and physical properties, versatility, ready availability and economic price. Of the common glasses it shows much less degradation with time to attack by water. 

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. 

Polyester resins are widely used due to their versatility and economic cost. Polyester exhibits a good combination of resistance to softening and deformation at elevated temperatures, good electrical properties and high resistance to corrosion as well as excellent weatherability [30, 31]. Structural applications, such as reinforced polyester containing glass fibre, comprise more than 80% of the market. Table 2.6 illustrates some of the physical parameters of polyester. 

This is the commonest reinforcing material. Glass fibre reinforced plastic (GRP), more commonly referred to as fibreglass, has many useful properties such as high tensile and compressive strength, hard smooth surfaces unreactive to chemicals, fire resistance, insulator of heat, electricity and sound, impervious to water, easily... 

Some polymerizable esters can be used as a copolymerizable internal plasticizer in technical applications. The best known of the group is diallyl phthalate (DAP), which is used to replace styrene, divinyl benzene, or methyl methacrylate in unsaturated polyester resins. It has a very low vapour pressure (300°C boiling point), leading to significant reduction in loss through evaporation. It considerably improves properties such as hardness, chemical resistance, hydrolysis resistance, electrical properties, and product life. It is particularly used in electrical applications, can be employed (after suitable preparation) in cold-cure systems, and shows high affinity to glass fibre. DAP can also be used as a reactive plasticizer with PVC resins. 

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