UHMW (Ultra High Molecular Weight Polyethylene) and PTFE Sheet(PolyTetraFlouroEthylene) are very similar materials, and yet very different at the same time. They both possess certain characteristics that make them similar to each other. For instance, they both have a very low co-efficient of friction, which means they are great for sliding applications and are easy to machine.
Both of these materials are very resistant to chemicals such as chlorine and some acids and have great wear resistance. They have low to no water absorption. They also are FDA approved for handling food. PTFE and UHMW Polyethylene are both nearly impossible to bond (without treatment) and are susceptible to sagging under tensile load which is called ‘creep’. These both have very low coefficient of friction and work well for wear strips, slide pads and truck liners to make it easy to empty. These two materials are different in many ways also, and choosing between the two materials for a specific job is critical.
Below are a few examples of how these two materials are different.
1. UHMW is a polyolefin and PTFE is a fluoropolymer. Polyolefins are double bonded carbon while Fluoropolymers are carbon and fluorine bonded. UHMW is a monomer which is consisted of one atom that will bond with another to form a polymer. PTFE is a polymer which is made up of a repeating chain of monomers.
2. PTFE has a higher temperature range than UHMW. The PTFE has a continuous use temperature of 500 degrees F. UHMW is much lower with a continuous use temperature of 200 degrees F and a melting point of 271 degrees F. The UHMW starts to become become soft at higher temperatures while the PTFE is much more resistant and with a melting point of 621 degrees F.
3. UHMW has higher abrasion resistance than PTFE. Both have great impact and wear resistance but because of UHMW having a molecular weight between 2-6 million making it the best wear resistance material in the plastic family, it makes it ideal to take wear and impact over a wider range and longer period of time without losing its properties.
4. UHMW has a much lower density than PTFE. This makes UHMW able to float in water while Fluoropolymers are significantly heavier (almost twice the density of UHMW) and would sink.
5. PTFE has excellent electrical and thermal properties. The virgin grade of PTFE is a better insulator and exhibits better electrical properties which can be used in radio frequencies, cables and circuit boards while UHMW cannot.
6. UHMW is much less expensive than the Fluoropolymers. Especially recently, PTFE has become harder to come by, and during the last 18 months there has been a global shortage of a key raw material called fluorspar that is used to make all Fluoropolymer materials. The ability to take lots of wear and tear and requiring low long term maintenance makes UHMW more cost effective.
7. The standard color of PTFE is Natural, which is a dense white. The UHMW comes in Natural (a deep milky white) or Black. The UHMW can be produced in many colors, and minimums are rather low. To obtain PTFE in colors is much more difficult, and would also have large minimum orders.
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Both the UHMW and the PTFE are available as sheet, sheets, sheeting, slab, bar, strip, panels, film, round rod, rods and block. Contact us for assistance with these or other shapes.
PTFE Sheeting Properties
Specific Gravity D792 2.14 – 2.24
Tensile Strength Yield D638 2,500 – 6,000
Tensile Modulus D638 80,000
Izod Impact – Notched D256 3.0
Hardness – Rockwell D785 D50 – D65
Deflection Temp @ 264psi D648 150
Deflection Temp @ 66 psi D648 250
Co. Thermal Expansion D696 5.5X10-5
UHMW Sheeting Properties
Specific Gravity D792 .93 – .94
Tensile Strength Yield D638 6,800
Coefficient of Friction – Static D1894 .25
Izod Impact – Notched D256 No Break
Hardness – Rockwell D785 R64
Vicat Softening Temp D1525 260
Deflection Temp @ 66 psi D648 174
Co. Thermal Expansion D696 11.0X10-5
These are just some examples of plastic materials being similar, and yet having very different properties. The PTFE Sheet and UHMW Sheet may appear very similar in color and can be used for some of the same applications, but when needed for a specific use or property needed, one might be dramatically better than the other. As the old saying goes, “You should never judge a book by its cover” and the same is true with plastic. Review the properties and test prior to choosing a final material for your application.
Call us for further assistance at 866-832-9315, or click here to contact us with your questions.
A wide variety of plastics are available in sheet form.
The term: ‘Plastic Sheet‘ or ‘Plastic Sheets’ is more of a general statement covering over a hundred types of plastic materials and plastic products. Some of the most popular plastic materials made as a sheet are:
In addition to the wide range of plastic materials available as plastic sheet, most of these materials are also available as: thin gauge or film, strip, plate, block, slab and plastic panels. The thin gauge or film materials are frequently available with or without a pressure sensitive adhesive also called ‘tape’. Sheet in some materials is available over 4.0″ thick and perhaps as thick as 8.0″ thick in a few materials. The standard sheet size on most of our plastic sheets is either 24″ X 48″ or the larger 48″ X 96″ sheet size; although some materials are available as: 48″ X 120″, 60″ X 96″ or 72″ X 96″. Contact us with with questions on your required piece sizes, we are happy to provide plastic sheets cut to size.
While there are lots and lots of different materials available as plastic sheet, there may only be one or two materials that are right for your application. We want to assist with your search. If you need help choosing the proper plastic material for your application, check out our free Plastic Material Selector Guide. Also, feel free to contact us for further assistance. As a leading plastic sheet distributor since 1975, we feel that we are your best choice as your new plastic sheet and sheets supplier. Give us a call at 866-832-9315. Google+
Next time you are cutting vegetables on your cutting board, the material most likely to be used is Polyethylene. Because it is stain, moisture and odor resistant, Polyethylene is a perfect choice. Other cutting boards made out of wood are more susceptible to bacteria and odors because they lack the properties that Polyethylene sheets offer, such as its chemical resistance and FDA approval for food contact. Polyethylene is a very durable and lightweight material that comes in many forms and is a great for a wide variety of applications.
NSF Approved Cutting Boards
The HDPE is available in .500″ thick in several FDA / NSF approved colors, and is great for use in kitchens where cross contamination is a problem.
The Ultimate Cutting Board
Polyethylene has many names. The most common are HDPE, LDPE, and UHMW. The difference has to with the molecular weight and branching which is when a monomer or atom is replaced by a longer chain of polymers (a long repeating chain of atoms). High Density is commonly used for milk jugs and food containers. Low Density is commonly used for bottles and plastic bags. UHMW, which has higher molecular weight (2-6 million) allows for an even transfer over the length of material which makes it stronger and able to be used for bearing applications due to its great wear resistance. Commonly used in the food and dairy industry, UHMW is a great replacement for other materials and solution to many problems. All of these polymers are derived from the same family but all have certain properties that make them a little different. HDPE provides great chemical resistance, with high impact strength and great energy absorption. LDPE has most of the same properties as High Density but is not as dense at 9.15, opposed to HDPE which is 9.34. It also has a lower tensile strength and easier formability.
UHMW is a strong material that has great durability and low co-efficient making it an ideal for sliding applications. Polyethylene offers a wide range of material choices and properties and has great durability that can be suitable for a number of applications. From the food industry to automotive, the kitchen or the warehouse, whatever your Polyethylene needs are; High Density, Low Density or UHMW, Polyethylene is a great choice.
Typical Resin Properties:
General Property
ASTM Test
Typical Value HDPE
Typical Value LDPE
Typical Value UHMW
Specific Gravity
D792
.941 – .965
.91 – .925
.93 – .94
Tensile Strength Yield
D638
3,800 – 5,500
1,400 – 2,000
6,800
Izod Impact – Notched
D256
2.0 – 3.5
>16
No Break
Vicat Softening Temp
D1525
257ºF
219ºF
260
Hardness – Rockwell
D785
D60 -70
D42 – 50
R64
Continuous Use Temp
–
-100 – 180ºF
174ºF
180ºF
Deflection Temp @ 66 psi
D648
171
124
174
Co. Thermal Expansion
D696
7X10-5
4.6 -5.5X10-5
11.0X10-5
Please contact us for more information on FDA and NSF approved plastic materials. Email us here, or call us at: 866-832-9315
