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UHMWPE and LDPE/HDPE are two different types of polyethylene (PE) materials, which have significant differences in molecular structure, performance, and application areas. The following are their main differences and characteristics:

1. Molecular structure

UHMWPE:

The molecular chain of high molecular polyethylene is very long, usually with a molecular weight between 3 million and 6 million, or even higher. Due to the long chain structure, it exhibits higher physical properties than ordinary polyethylene.

Ordinary polyethylene (LDPE/HDPE):

Ordinary polyethylene has a lower molecular weight. The molecular weight of LDPE is usually around hundreds of thousands, while HDPE is slightly higher. Their molecular structure is relatively simple, the molecular chain is shorter, and the molecular weight is lower than UHMWPE.

2. Mechanical properties

UHMWPE:

Extremely high wear resistance: Due to its long molecular chain structure, UHMWPE exhibits excellent wear resistance, far exceeding ordinary polyethylene. This makes it widely used in sliding surfaces and high-friction environments.

High strength and high toughness: Even at low temperatures, UHMWPE has excellent impact resistance and tensile strength, and is often used in industrial applications that require high loads and high impact resistance.

Low friction coefficient: Its surface is smooth and has a low friction coefficient, so it is suitable for sliding systems, conveyor belts, ice rinks, etc.

Ordinary polyethylene (LDPE/HDPE):

HDPE: has high tensile strength and impact resistance, but compared with UHMWPE, it has poor wear resistance and slightly lower toughness.

LDPE: has good flexibility but low strength, suitable for applications such as film and packaging.

3. Temperature resistance

High molecular weight polyethylene (UHMWPE):

It can be used in a wide temperature range, generally from -200°C to +80°C. It still maintains good toughness and strength in low-temperature environments, so it is widely used in low-temperature environments such as cold chain transportation and ice rinks.

Ordinary polyethylene (LDPE/HDPE):

HDPE has good high-temperature resistance, generally with a temperature range of -50°C to +90°C, suitable for general industrial applications.

LDPE has a relatively poor heat resistance and a narrow temperature range, generally between -50°C and +70°C.

4. Chemical properties

UHMWPE:

It has very strong corrosion resistance to chemicals, oils, acids, and alkalis, and can be used for a long time in harsh chemical environments. In addition, it is not easily damaged by ultraviolet rays, so it is suitable for outdoor applications.

Ordinary polyethylene (LDPE/HDPE):

HDPE has a good tolerance to most chemicals but may be affected in some extreme chemicals or solvent environments.

LDPE has poor tolerance to acids, alkalis, and oils, and is suitable for mild chemical environments.

5. Application areas

UHMWPE:

Environments with high wear resistance requirements: such as conveyor belts, sliding surfaces, ice rinks, roller skating rinks, and mechanical parts (such as gears, bearings, etc.).

Medical field: such as artificial joints, surgical instruments, etc., because of its good biocompatibility and corrosion resistance.

Aerospace and military industry: such as bulletproof materials (such as bulletproof vests), impact protection, etc.

Ordinary polyethylene (LDPE/HDPE):

HDPE: widely used in packaging materials (such as bottles, containers, pipes), plastic bags, furniture, toys, etc.

LDPE: mostly used in light packaging materials such as films, food packaging, shopping bags, and plastic wrap.

6. Processability

UHMWPE: Due to its long molecular chain, the processing process requires higher temperature and pressure, and usually adopts extrusion molding, calendering molding, and other processes. The processing is difficult, but once formed, the durability and performance are very outstanding.

Ordinary polyethylene (LDPE/HDPE):

Relatively easy to process, suitable for conventional processing methods such as blow molding, injection molding, and extrusion.

Summary: **UHMWPE** has significant advantages over ordinary polyethylene (LDPE/HDPE) in terms of wear resistance, strength, toughness, low-temperature resistance and chemical corrosion resistance. It is suitable for high-strength, low-friction environments.

Ordinary polyethylene (LDPE/HDPE) is widely used in daily life and general industry, with a lower price, and is suitable for general packaging and container purposes.