About Electrical, UV, & Outgassing Properties For Plastic Manifolds
Whether you're a seasoned engineer or just starting out, this section will walk you through the essential considerations for electrical and outgassing to create efficient and reliable plastic manifolds. We'll focus on the other two main critical aspects: electrical properties and outgassing. We will define a few terms that are integral to understanding these as a whole. This will also give ground-level knowledge of the various terms used later on when delving further into our materials pages and exploring those in greater detail.
Regarding Electrical Properties for Plastic Manifolds
In certain applications requiring some element of electrical compatibility, engineers cannot deny the importance of a few key factors, like volume resistivity with both dielectric constant and strength. They play an essential part in a manifold's overall performance and longevity. Different applications demand certain properties, and choosing the right plastic material that fits the job stands as one of the most important factors for consideration.
Selecting Materials for Electrical Performance
When selecting materials for electrical purposes in plastic manifolds, we strongly urge you to keep these factors in mind. Many types of plastic are inherently insulating, however, some do a better job than others and depends greatly on the purpose of the product. Does it need to resist electrical input or assist in electrical efforts? What other properties does it require to function and perform optimally?
Dielectric Strength
If the product needs some sort of electrical support element, we highly recommend choosing plastics with superior dielectric strength to prevent electrical breakdown or system failure. Keeping electricity from interfering increases safety for not only anyone working with the product but also any other adjoining assemblies or components. Controlling electrical elements increases predictability and reliability. Many experts name materials like UHMW, PET, and CPVC as having the highest resistance to electrical conductivity.
In that vein, thermal stability marks itself as crucial for sustained performance. Designers need to ensure that their plastic can withstand temperature variations without compromising those electrical properties, again protecting the operators and their systems.
Dielectric Constant
Alternatively, the plastic manifold may need to assist in electrical conductivity. If that is the case, then we recommend seeking a material with a high dielectric constant.
In the chart here, it displays those plastic materials that have the ability to help electrical inputs and purposes and which are not the best. In the case of needing more electrical conductivity support, most manufacturers can add special additives to enhance a manifold's conductivity. However, this can also add another level of complexity to the project. We recommend to consult with an expert to assess a project's requirements to determine its necessity.
Data courtesy of Omnexus
Data courtesy of Omnexus
Volume & Surface Resistivity
Volume resistivity measures how difficult electricity's journey is from one end to another based on a material's thickness. Those materials with high volume resistivity create more challenges for electricity to flow through the material. This is indirectly related to surface resistivity as well as dielectric strength, however, they still act as separate concepts.
We have detailed out those volume resistivities for different plastic materials in this chart here.
Surface resistivity applies to the surface of a plastic material (in this case). Whether the material has smoother "roads" for the electricity to pass or harbor more obstacles, this influences a material's electrical performance that engineers also need to consider when selecting a material for their product.
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Regarding UV Resistance
Many industries utilize UV light for varying purposes or need resistance to it for weather-related purposes (among several others). As we keep saying, some materials have a higher resistance to such forces than others. If you know that your product will need to meet the following criteria, then we suggest a higher-performance material that would suit its purpose.
- Durable performance against prolonged sun exposure
- Fade resistance
- Weatherproof reliability
- Assured longevity
We have detailed some of our most popular plastics used and their associated UV resistance grades in the following table.
| UV Resistance | |
|---|---|
| ABS | Poor |
| Acetal | Poor |
| Acrylic | Good |
| CPVC | Fair |
| CTFE | Good |
| ECTFE | Good |
| ETFE | Good |
| HDPE | Poor |
| Noryl | Good |
| Nylatron | Poor |
| Nylon | Poor |
| PBT | Fair |
| Peek | Good |
| PES | Fair |
| PET | Fair |
| Polycarbonate | Fair |
| Polysulfone | Fair |
| PP | Fair |
| PPS | Good |
| PVC | Good |
| PVDF | Good |
| Teflon® | Good |
| Torlon | Excellent |
| UHMW | Fair |
| Ultem® | Excellent |
Data courtesy of Omnexus
Considering Outgassing
Outgassing means the release of gases trapped within a plastic. Each plastic material will have some number of gases which will release over its lifetime. The release of gases is especially important in vacuum applications and where off gassing can affect the results.
Here is a table of materials and their likelihood of outgassing.
| Outgassing | |
|---|---|
| ABS | High |
| Acetal | Moderate |
| Acrylic 1,2 | High |
| COC/COP | Low |
| CTFE | Low |
| ECTFE | Low |
| HDPE | High |
| Noryl | High |
| Nylatron | High |
| Nylon | High |
| PEEK | Low |
| PET | Low |
| Polycarbonate 1,2 | Moderate |
| Polysulfone | Low |
| PP 1 | Moderate |
| PPS | Low |
| PVC 1,2 | High |
| PVDF | Low |
| Tecadur | Low |
| Teflon® 1 | Low |
| Torlon | Low |
| Ultem® | Low |