مجموعة: HDPE/UPE/PP/PC/PMMA plate
HDPE (High - Density Polyethylene) and UPE (Ultra - High Molecular Weight Polyethylene) have the following differences:
1. Molecular Structure and Weight
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HDPE:
- It has a relatively high density among polyethylenes, typically in the range of 0.941 - 0.965 g/cm³. The molecular chains of HDPE are more closely packed and have a linear structure with fewer branches. The average molecular weight of HDPE is lower than that of UPE. For example, the molecular weight of HDPE usually ranges from 100,000 to 300,000 g/mol.
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UPE:
- As the name implies, it has an ultra - high molecular weight. The molecular weight of UPE can be as high as several million g/mol (usually in the range of 3 - 6 million g/mol). The molecular chains are very long and have a high degree of entanglement, which gives it unique physical properties.
2. Mechanical Properties
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HDPE:
- It has good tensile strength, generally in the range of 20 - 30 MPa. It is rigid enough for many applications such as pipes and containers. It also shows good impact resistance, which means it can withstand a certain amount of external force without breaking easily. For example, HDPE pipes can endure the pressure of water flow and the impact of installation and handling.
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UPE:
- UPE has excellent abrasion resistance, far superior to HDPE. It can withstand heavy wear and tear, making it ideal for applications such as conveyor belts and wear - resistant linings. In terms of tensile strength, UPE can reach very high values, often over 30 MPa, and its elongation at break is also relatively high, which allows it to have good flexibility and toughness under stress.
3. Processing Characteristics
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HDPE:
- HDPE is relatively easy to process. It can be molded, extruded, and injection - molded using common plastic processing techniques. It has a relatively wide processing temperature range. For example, in extrusion processes, the temperature is usually between 180 - 230°C, depending on the specific grade and additives.
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UPE:
- UPE is more difficult to process due to its ultra - high molecular weight. It has a high viscosity, which requires special processing equipment and techniques. For example, it often needs to be processed at higher temperatures and pressures to achieve good flowability. Moreover, the processing speed is usually slower than that of HDPE to ensure the quality of the product.
4. Application Areas
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HDPE:
- Widely used in the manufacture of pipes for water supply, gas supply, and sewage systems due to its good pressure resistance and chemical resistance. It is also used to make plastic bottles, containers, and various injection - molded products such as toys and household items.
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UPE:
- Commonly used in applications where extreme wear resistance is required, such as in the mining industry for chute linings and in the material handling industry for conveyor components. It is also used in biomedical applications such as artificial joints due to its biocompatibility and low friction characteristics.
What are the specific applications of HDPE and UPE?
How to distinguish between HDPE and UPE visually?
What are the main differences in performance between HDPE and UPE?