Anti-Static Properties of Materials
Testing, measurement and control of anti-static properties in materials.
Intertek helps clients understand the anti-static properties of materials. Such knowledge is crucial in many applications, where the build up of static charges can lead to hazardous or problematic electrical discharges.
The ability of a material to discharge damaging electrical charges is affected by purity, level of contamination, moisture content and physical form (including surface roughness) and other factors. For mission critical applications it is important to carry out a proper evaluation of these static properties, rather than relying entirely on just theoretical materials properties.
Intertek provides test methods to assess anti-static properties of materials. Measurements are typically made on solid substances, but can also be carried out on powders and liquids.
Static properties test measurements:
- Volume Resistivity is a measurement of the bulk electrical properties of the material, but is not a particularly good indicator of antistatic performance, which can be dominated by surface effects or inhomogeneous contamination
- Surface Resistivity is more generally used to assess antistatic properties, but results can still sometime be misleading - for example if a relatively conductive sheet of polymer has a thin insulating surface layer.
- Static Charge Decay measurements mimic more closely real-life performance. Here a static charge is deposited onto the surface of the material, and the time taken for this to decay is monitored with an electrostatic voltmeter
- Static Charge Mapping can visualise the build up of charge on the surface of a material, which is useful in cses where the surface charge is inhomogeneous, or even consists of regions of opposite polarity
Applications for antistatic measurements include:
- Packaging materials for electronic components
- Polymer film manufacturing problems
- Polymer film and sheet handling problems (sticking & binding)
- Powder handling and ignition analysis