Comparative tracking resistance

Nylons have excellent arc and tracking resistance. Arc resistance is not affected by moisture or temperature up to about 100°C. Comparative tracking resistance of most immodified nylons is greater than 600 V. Incorporation of additives such as flame retardants often reduces the electrical properties because of the introduction of ionic species. 

Nylons have excellent arc and tracking resistance. Arc resistance is not affected by moisture or temperature up to about 100°C. Comparative... 

Compared with the phenolic resins they have a better colour range, track resistance and scratch resistance. They have a similar order of heat resistance, although their dimensional stability when exposed to hot dry conditions is not so... 

The nonaromatic nature of these maicrials provides for improved uv resistance and arc-track resistance compared to conventional epoxies The best properties arc generally achieved with anhydride and phenolic curing agents. 

MF moldings are superior to UF products in lower water absorption (see Table 4.21), greater resistance to staining by aqueous solutions such as fruit juices and beverages, better retention of electrical properties in damp conditions, better heat resistance, and greater hardness. Compared with the phenolic resins, MF resins have better color range, track resistance, and scratch resistance. MF resins, are however, more expensive than general-purpose UF and PF resins. 

Silicone laminates are useful from cryogenic temperatures to about 260°C. The dielectric properties of silicones are particularly useful. Both dissipation factor and dielectric constant are low at room temperature and remain relatively constant up to 150°C. Because of the presence of the silicon atom, silicone laminates have good arc- and track resistance. The physical properties of silicones are not greatly influenced by aging, but compared with laminates that are based on other resins, the flexural and tensile strengths of silicones are not unusually high. Silicone laminates are used in electronics, heaters, rocket components, slot wedges, ablation shields, coil forms, and terminal board. 

The apparatus supplied by ATS FAAR (Table 18.6) evaluates, during a short period of time, the low-voltage (up to 600 V) track resistance (or comparative tracking index) of... 

PAEK can be used as good electrical insulators in a wide range of environments and over a wide range of temperatures. The polar nature of the carbonyl group means that materials such as fluoropolymers have superior dielectric constants and dissipation factors. However, relative to fluoropolymers, PAEK insulation offers lower toxicity in fire situations and more resistant mechanical properties. PAEK can have a relatively low comparative tracking index which measures susceptibility to electrical breakdown on the surface of an insulator. Possibly this reflects the relatively easy degradation of PAEK to carbonaceous char. 

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