PTFE is one of the most commonly used filtration membranes. But there are different factors to consider when choosing the specific ones you need. When you know more about PTFE filters, you can make the right selection for your situation. Keep reading to find out more about the characteristics, uses, and options when it comes to PTFE.
What to Know About PTFE
First, as mentioned, PTFE is a thermoplastic polymer, which means it is solid at room temperature. It also has a melting point of 621°F, though it begins to lose some of its abilities as the temperature begins to rise above 500°F. As a fluorocarbon, PTFE achieves its properties through the aggregate effect achieved from the carbon-fluorine bonds.
The co-efficient of friction for PTFE is 0.1 or less, which is why this material has proven efficient for a variety of different applications, including those mentioned previously. The discovery of its dielectric properties also enhances the array of uses available, ensuring PTFE is useful as a cable insulator, and a circuit board material. Not only that but it offers high bulk resistivity and is chemically inert. This means that it cannot be cross-linked and will creep just enough to meld to a secondary surface.
All of this allows PTFE to be used in even more applications, including plain bearings, slide plates, and gears. It can even be amended utilizing mineral oil or molybdenum disulfide for additional applications and uses.
Where to Use PTFE Filters
Typically, PTFE filters are single use filters, but because of their chemical inertness they can be used even for highly acidic samples and testing. These include aggressive solvents, aerosol sampling, degassing solvents, venting applications, and organic-based HPLC. All of this can be done without danger of corrosion and also while maintaining a high level of purity and exacting detail.
PTFE syringe filters come with a range of filter membranes compatibility with a range of different chemicals, which allows for increased filtration, chemical stability, and more. It is, therefore, useful in labs and industrial situations.
Benefits of PTFE Filters
There are a range of benefits associated with PTFE filters, and we will review the most important of these here:
- Resistant to acids, bases, and solvents
- Hydrophobic
- Interference-free chemical determinations
- Low tare mass
- Temperature resistant up to 500°F
- Meets NIOSH Method 5517 specifications
- Versatile for size-selective samplers
Resistant to acids, bases, and solvents
PTFE filters are extremely strong and do not cause reactions when exposed to acids, bases or solvents. They are chemically inert, which enables them to filter these materials without damage to the filter or the material themselves.
Hydrophobic
PTFE filters are not dampened by air humidity, which makes them more useful and versatile than hydrophilic filters. Because the filter is made solely with PTFE, this means that there is no chance of wetness occurring, and instead the filter is considered ‘permanently hydrophobic.’
Interference-free chemical determinations
PTFE filters allow for chemical determination testing without any measurable interference. This enables testing to be more precise and outcomes to be considered purer.
Low tare mass
PTFE itself is low in overall weight, which enables it to be used more accurately with gravimetric analysis and more. The tare mass of other materials can require additional calculations and care to ensure they are done accurately. This is not required with PTFE filters.
Temperature resistant up to 500°F
The ability to continue operation even in extreme temperature situations enables PTFE to be used in broader situations. The material is considered autoclavable and therefore allows for enhanced versatility.
Meets NIOSH Method 5517 specifications
The 13mm filter specifically meets these specifications, falling under CDC guidelines for polychlorobenzenes.
Versatile for size-selective samplers
The overall uses and features of PTFE are even more versatile when considering the abilities related to size-selective samplers. This enables the PTFE filters to be utilized in most lab and industrial applications.
PTFE Syringe Filters vs. Membrane Filters
In considering the proper type of filter within the category of PTFE, it is essential likewise to consider both syringe filters and membrane filters. Each can provide the quality features and abilities required for any form of sampling and testing.
PTFE syringe filters are designed to be durable and offer accuracy and quality results. They do this at a low price point, making them an excellent choice when it comes to most situations and most testing requirements. They can be found in different diameters and can be used both sterile and non-sterile. Alongside this, they provide microfiltration and can be used for different industries that include agriculture, environmental, biotechnology, and more.
PTFE membrane filters offer enhanced accuracy in the way of pore size distribution, ensuring high quality and strength as well as flexibility. Perhaps more importantly, these filters provide consistency and therefore reproducibility, essential in carrying out any scientific tasks and lab work. These membrane filters are also available as PTFE membrane roll stock as well, providing even more features and options in use of the materials.
PTFE Filters in Scientific Filtration
When conducting scientific filtration, PTFE filters can be used for 1) liquid samples with 2) insoluble impurities that are 3) high quality materials, 4) representing a low level of extractables. All of these qualifications are met for this type of situation and the filter will provide quality and versatility in all such applications.
Types of PTFE Filters
There are a range of different PTFE membrane filters that come in a range of diameter and pore sizes to provide additional features and capabilities. These range from 13mm to 47mm filters, with pore sizes ranging from 0.3 to 10.0. In this manner, PTFE filters can be used for an even wider array of purposes and this provides an even better benefit overall for users and the scientific community as a whole.
Selecting the Proper Filter Characteristics
When it comes to selecting a filter for any task there is a prescribed process involved which requires four simple steps. These steps can be done with a filter media selector and include:
- Deciding on the necessity of prefiltration for the application.
- Choosing a membrane filtration material based on qualities such as aqueous, non-polar, and protein.
- Selecting a diameter typically of <10ml, <100ml, or <250ml to determine the mm diameter of the filter.
- Ensuring the pore size, based on micron size of the column of >3um or <3um.
In carrying out this process it is also essential to ensure that chemical compatibilities are followed. PTFE is designed to be compatible with all types of materials. We will take a look at this chemical compatibility guide and the different types of materials that PTFE is considered fully compatible with:
- Ketones
- Hydrocarbons
- Amines & amides
- Halogenated hydrocarbons
- Esters
- Organic oxides
- Alcohols
- Bases
- Acids
In providing full compatibility to each of these categories of materials, PTFE filters are therefore considered extremely useful and versatile as a whole.
Applications of PTFE Filters
There are a range of different applications that PTFE filters can be used for, however some of the most common include:
- Food and drink
- Steam filtration
- Water treatment
- Chemical industry
- Pharmaceutical industry
- Solvent sterilization
- High purity gas filtration
- Gas sterilization filtration
- Vacuum filtration
- Sterile exhaust filtration for fermentation tanks
PTFE Filtration Systems Offer Everything You Need
In general, PTFE filters are capable of a range of different processes and will offer the ability for those in the industrial or scientific communities to perform testing and more quickly and accurately. These PTFE syringe filters and membrane filters are designed to provide high quality and efficiency while also keeping the overall price point lower, enabling even more service.
The key to PTFE filters is simply determining the best manner in which to utilize them for different businesses and more. Versatility is the hallmark of this product, and it is the most important of all features in ensuring that the outcome will be accurately executed.