1.Molecular weight and material strength
UHMWPE: Its molecular weight usually exceeds 1.5 million (up to 10 million), and its molecular chain length is 10 to 20 times that of HDPE. 58. The ultra-long molecular chain structure endows it with extremely high tensile strength (≥40MPa, ISO 527) and impact resistance (≥110kJ/m², ISO 179).
HDPE: Its molecular weight is generally between 100,000 and 200,000, with relatively low strength (tensile strength is approximately 20-30 mpa), and its impact resistance is only 1/4 of that of UHMWPE.
2. Wear resistance and self-lubrication
UHMWPE
Its wear resistance is more than 10 times that of HDPE and 6 times that of carbon steel.
The surface friction coefficient is only 0.07-0.11 (close to polytetrafluoroethylene), and it has excellent self-lubricating properties, making it suitable for oil-free lubrication scenarios.
HDPE: It has relatively low wear resistance and needs to rely on additives to enhance performance. Its coefficient of friction is approximately 0.15-0.25.
3. Chemical corrosion resistance and temperature adaptability
UHMWPE
Resistant to strong acids (such as 98% sulfuric acid), strong alkalis (such as 50% NaOH), and organic solvents, with an applicable temperature range of -269℃ to +80℃.
It still maintains toughness in liquid nitrogen (-196℃).
HDPE: It has poor chemical resistance (only resistant to weak acids and alkalis), with an upper working temperature limit of 60℃ and a low-temperature embrittlement temperature of approximately -60℃ to 110.
4. Differences in application fields
UHMWPE
Extreme scenarios: wear-resistant lining plates for mines, inner lining plates for dump trucks, anti-radiation components for satellites, deep-sea cables.
High-end demands: Bulletproof vest fibers (strength 35cN/dtex), food-grade conveying pipes (FDA certified).
HDPE
Conventional scenarios: municipal water supply and drainage pipelines, gas transmission, agricultural irrigation.
Cost-sensitive areas: Packaging materials, low-cost containers 9.
5. Processing and Economy
UHMWPE
The processing difficulty is high, requiring hot molding or gel spinning processes, and the cost is about 3 to 5 times that of HDPE.
Suitable for high value-added products (such as lithium battery separators, bulletproof fibers).
HDPE
It is easy to be hot-melt connected and extruded, with low cost and suitable for large-scale production.
Summary
Choose UHMWPE: When it is necessary to deal with extreme wear, impact, low temperature or corrosive environments and the budget is sufficient.
Select HDPE: conventional working conditions, cost-sensitive scenarios or those requiring rapid processing.
