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Time:2019/12/18 12:48:03
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I. Product Features

The molecular weight of ultra-high molecular weight polyethylene (UHMWPE) makes it an engineering plastic rich in outstanding thermoplastic performance at moderate price and concentrated with advantages of various plastics, for its general features such as resistances to wear, impact, corrode, water-absorption, and low temperature, auto-lubrication, impact absorption, sanitary non-toxicity, non-adhesiveness, lower density. In reality, there is no single polymeric material combined with so many excellent features of the UHMWPE so far.

 

1. Resistance to wear

The resistance of UHMWPE against wearing ranks first of plastics, exceeding that of some metals, as is illustrated in Fig. 1 Wearing-Resistance Comparison of UHMWPE and Other Materials, where, the wearing resistance index against mortar is one-fifth of PA66 only, one-tenth of HEPE and PVC, compared to other engineering plastics; fortunately, compared to metals, this index is one-seventh of carbon steel, and 1/27 of brass. So good performance in resistance to wear make it impossible for general plastic tests to measure its resistance to wear, and a unique special utensil to test the resistance against mortar-wearing is designed to satisfy the demand. The resistance of UHMWPE to wear is positively proportional to its molecular weight, the higher of its molecular weight, the better the resistance.

 

2. Resistance to impact

The resistance of UHMWPE to impact leads the list of all engineering plastics, illustrated in Fig. 2 Impact-Resistance Comparison of UHMWPE and Other Engineering Plastics, where its impact-resistance is approximately 2 times that of PC, over 10 times of that of POM and PBTP. So good performance in impact resistance make it hard to destroy and crack it using general impact testing methodologies. Its resistance to impact increases as its molecular weight becomes big until reaching 1.5 million where its resistance to impact starts to fall gradually as its molecular weight increases. It is worthy of attention that it maintains outstanding resistance to impact in liquid nitrogen at -195oC, which no other plastics are enabled to match. In addition, its surface hardness becomes higher when multiple impacts are applied to.

 

3. Auto-lubrication

UHMWPE is extremely low in friction factor (0.05 to 0.11), so as to perform well in terms of auto-lubrication, illustrated in Table 1 Friction Factor Comparison of UHMWPE to Other Engineering Plastics, where its dynamic friction factor is one-second of that of PA66 and POM conditioned on water lubrication, and second only to that of polytetrafluoroethylene (PTFE), or the best plastic in terms of auto-lubrication, without any lubrication. It works much better than steel and brass with lubricating oil added when applied to sliding and/or rotating. Thus, in the field of friction science UHMWPE is granted with ideal anti-frication material in cost and/or performance.

 

4. Resistance against chemicals

UHMWPE works well against chemicals with exception of oxidizing acid solution. Within specific scopes of temperature and concentration, it is enabled to resist various corrosive media including acid, base, and salt, together with other organic media (except solution of naphthalene).

 

30 days of impregnation bath in 80 organic solvents at 20oC and 80oC are failed to make the surface of it appear abnormal phenomenon, and almost no change in physic features.

 

5. Impact Absorption

UHMWPE is rich in outstanding impact absorption and good noise-damping capacity, that is to say, it tops impact absorption value of all plastics, and works well in noise deadening.

 

6. Resistance against low temperature

UHMWPE has excellent feature against low temperature. At temperature of liquefied nitrogen (-269℃), it still has ductility to provide components against low temperature for nuclear engineering industry.

 

7. Sanitary non-toxicity

UHMWPE is sanitary and non-toxic, allowed contacting foods and medicines directly.

 

8. Non-adhesiveness

UHMWPE is very poor in surface absorption, and second only to that of polytetrafluoroethylene (PTFE), which is regarded as the best of persistent adhesiveness, so as to make its product impossible to persist in adhesiveness from other materials.

 

9. Resistance to absorb water

UHMWPE has as low water-absorbing ratio as less than 0.01%, second only to 1% of PA66, so as to allow no drying treatment before shaping.

 

10. Density

UHMWPE, compared to other engineering plastics, is low in density relatively.

 

11. Tensile strength

Due to its featured characteristics in necessary direction-oriented tensile capability, UHMWPE owns unmatched high tensile strength, so that fibers with high elastic modulus and strength is allowed to obtain by means of freezing-gel spinning, having tensile strength up to 3 to 3.5GPa, and elastic modulus up to 100 to 125GPa. Its strength of fiber proportion is the highest of all commercial products so far, 4 times greater than carbon fiber, 10 times greater than wire-steel, and 50% greater than aramid fiber.

 

II. Applied areas of products

Rails made of UHMWPE engineering plastics are applied in textile, paper-making, food processing sectors at early stage, owing to its outstanding performance in thermoplastic shaping. With the development technology, different products of it can be obtained through different processing methodologies, to enlarge its applications. Currently in addition to said areas, important applications are widened to cover mining / construction machinery, traffic and transportation, complex lining, and even nuclear industries. UHMWPE is widely used in more vast areas by foreign peers.

 

III. Nine major advantages

1. Less in wearing,

2. Lower in fraction,

3. Auto-lubrication (no lubricant oil required),

4. Resistance to impact,

5. Application temperature scope: -200oC to +80 oC ,

6. Shock absorption,

7. Resistance against moisture deterioration in damp conditions,

8. High resistance against chemicals, and

9. Resistance against corrosion.