UHMWPE Material As Polyethylene PE Family Leader

August 11, 2024

teflon standard, an explanation of the UHMWPE material, Polyethylene PE family leader

Development history: UHMWPE was first industrialized by American Allied Chemical Company in 1957. Since then, Germany Hoechst Company, the United States Hercules Company, Japan Mitsui Petrochemical Company has been put into industrial production, and efforts to develop its applications. 80's, the world's average annual growth rate of 8.5%, into the 80's, the growth rate of up to 15% to 20%, and China's average annual growth rate of more than 30%.

Ultra-high molecular weight polyethylene (UHMWPE) is a thermoplastic engineering plastic with excellent comprehensive performance, its relative molecular mass of more than 1.5 million, commercially available molecular weight of 1.5-10.2 million is the main.

UHMWPE Advantages

1.Excellent abrasion resistance: The best abrasion resistance of all plastics, and many metallic materials have less regular abrasion resistance than it. As the molecular weight of polyethylene rises, the material becomes even more wear resistant. Some old iron (Teflon) is not convinced, as one of the three major solid lubrication PTFE, the coefficient of friction in the plastic resin inside the lowest, but the actual abrasion amount of wear test, especially in the face of hard materials, for the process of wear, UHMWPE is superior to the old iron! The following figure is the data of the construction industry.

UPE wear resistance reason analysis:

(1)Molecular structure UHMWPE molecular chain is longer and more regular, which makes it in the friction and wear, can be better dispersed stress, reduce the local wear damage. PTFE molecular chain is relatively short, and the intermolecular bonding is weak, in the friction process is more likely to appear molecular chain slippage and fracture.

(2)Crystallinity UHMWPE has high crystallinity, the crystalline region can provide better wear resistance, PTFE has relatively low crystallinity, wear resistance is relatively weak.

2.Extremely high impact resistance: the impact strength is related to the molecular weight, when the molecular weight is lower than 2 million, the impact strength increases with the growth of molecular weight, and reaches the peak value around 2 million, after that, the impact strength will decrease when the molecular weight rises again. In the low temperature (even liquid helium -269 ℃ temperature) still has a strong impact resistance, which makes the application of UHMWPE extended to the field of low temperature engineering.

3.Its room temperature impact resistance is extremely high, known commercial impact PC most able to beat the Saudi Arabia base EXL9111, notched impact 104, but UPE impact 200 is also common, any one UPE impact poor little brother have 120 + impact on the whole family of PC can be a second, not to mention low-temperature impact. We may not have a concept of the strength of the UPE impact of the strong, look at the picture above, South Korea U050H physical properties, notched impact up to 200.

4.Very low coefficient of friction: very wear-resistant and low coefficient of friction, coefficient of friction 0.1-0.3, in the environment of water as a lubricating medium, UPE reduces to the range of 0.05 to 0.10, comparable to PTFE. self-lubricating is good, it is the ideal bearing bushings, sliders, lining materials use UPE as the friction parts of the equipment, you can increase the wear-resistant life and energy saving.

5.Very low water absorption and weather resistance: UPE has a very low water absorption rate, almost does not absorb water, does not swell in water.UPE molecular chain in the unsaturated molecular chain is very small, the molecular weight of the larger is not easy to be affected by ultraviolet rays, the application of the application of the only need to add the anti-aging agent, and its weather resistance is very strong.

The above advantages, some friends may not have contact with UPE materials, but I believe that in the construction site to play ash, machinery factories, port terminals and shipyards brothers, should have contact with the construction site of the UPE protective plate, cushion plate, buffer blocks in a variety of machinery, eccentric wheels, rod bushings, why is so resistant to grass, right? Encounter UPE pieces you just hard pressure, just punch, randomly press the ground friction! Other materials in front of the UPE plate are little brother.

Continue to analyze other advantages of UPE

Good chemical resistance: except for concentrated nitric acid and concentrated sulfuric acid, it will not be corroded in all alkaline and acidic liquids, and it can be applied in concentrated hydrochloric acid at a temperature of 80℃, and it can be stabilized in less than 20% of nitric acid and less than 75% of sulfuric acid, and it is stable to water and liquid washing. However, it is extremely soluble in aromatic materials or halogenated material compounds (especially in the condition of higher temperature).

Good low-temperature performance: very excellent low-temperature resistance, at a low temperature of -269 ℃ still has a certain degree of ductility, there is no sign of brittle crack.

Excellent electrical properties: in a wide range of temperatures and frequencies, volume resistance of 10-18 ohms, breakdown voltage of 50KV/mm, dielectric constant of 2.3, very small changes in electrical properties. It is suitable to be used as structural material of electrical engineering and paper mill in the range of heat-resistant temperature.

Non-toxicity: tasteless, non-toxic, non-odor, non-corrosive itself, with physiological circulation and physiological adaptability, by the U.S. Food and Drug Administration (FDA) and the U.S. Department of Agriculture (USDA) allowed to be used in contact with food and drugs.

Disadvantages of UHMWPE

Heat resistance, heat distortion temperature of 85 degrees or less, if divided by heat resistance, Plastics Jun that UPE can only stay in the general-purpose plastics camp, can not give it the status of engineering plastics. Compared with Teflon, the lowest temperature resistance of PVDF is still low! But wear resistance and impact resistance is very capable of fighting, must be high!

Poor processing and molding; high viscosity, pure UPE is not suitable for injection molding, the application is limited, Teflon PTFE such as although not suitable for injection molding, but the family has FEP, PFA and other suitable for injection molding processing, the application is more broad, Plastic Jun look forward to more large factories to join the research of modified UPE, help molding sex.

Outer surface hardness, rigidity and creep resistance is not as good as general engineering plastics; some domestic and foreign companies are developing modified UPE.

The coefficient of expansion is on the large side, and precision parts can't be done. This is not comparable with fluorine plastic!

Flame retardant, UPE and ordinary PE no difference HB, and fluorine plastic natural flame retardant V0!

Summary: UPE against the standard Teflon is a bit overstated, UPE performance is very strong, such as impact and wear resistance, defects are also very obvious, the good thing is that the price compared to fluorine plastics is quite cheap, 2-6w a ton of the main, and specific gravity is low, close to the ordinary hdpe. If you use machined products, if there is no need for high temperature resistance, no flame retardant (modified), the precision requirements of the product is not high, the overall cost is about 20% of Teflon, is definitely the most cost-effective alternative to Teflon.

Author:

Ms. Tina

E-mail:

sales@honyplastic.com

Phone/WhatsApp:

+8618680371609