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Jai Ganesh

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Chlorinated polyethylene

Gist

Chlorinated polyethylene (CPE), a thermoplastic elastomer, is produced by chemically substituting chlorine onto linear polyethylene, offering properties like resistance to heat, oxidation, and ozone, and is used as a rubber and modifier for resins.

Summary

Chlorinated polyethylene (PE-C or CPE) is an inexpensive variation of polyethylene, where chlorine is substituted for some of the hydrogen atoms. CPE has a chlorine content from 34 to 44%.

Due to its soft, rubbery texture, CPE is added to polyvinyl chloride to increase its impact and weather resistance. Furthermore, it is used for softening PVC foils, without risking plasticizer migration.

Chlorinated polyethylene can be crosslinked with peroxides to form an elastomer which is used in cable and rubber industries. When chlorinated polyethylene is added to other polyolefins, it reduces the flammability. Chlorinated polyethylene is sometimes used in power cords as an outer jacket.

Chlorinated polyethylene is listed on the Living Building Institute's Red List of materials that cannot be used.

Details

Chlorinated Polyethylene is a family of thermoplastics that are produced by the chlorination of high-density polyethylene.

Chlorine content can be as high as 70% by weight but most grades have chlorine content in the 25% up to 42% range.

Properties

CPE offer a range of properties and have inherent resistance to heat, oxidation, and ozone due to their saturated molecular backbone, which is further enhanced by molecular modification with chlorine.

Advantages

• Good anti-ageing property and excellent weatherability.
• Good anti-combustion, no self-ignition
• Good low-temperature flexibility. Used in UPVC products
• Good endurance to chemicals.
• Good processing ability. It’s easy to be shaped
• Good stability

What is it used for?

Although it can be used by itself as special synthetic rubber, CPE is a versatile product that is compounded with other materials to achieve different properties and products. It is widely used as a thermoplastic elastomer (TPE), rubber and modifier for resins (PVC, PE and ABS)

Its main use is as an impact modifier that improves the impact resistance and lowers the cost of rigid and otherwise brittle (unplasticised) PVC. Building products include rainwater goods, below ground drainage, profiles, doors and windows.

Additional Information

Chlorinated polyethylene (CPE) is a unique type of polyethylene that contains 34 to 44% chlorine in its main chain. This distinctive composition gives CPE a wide range of properties that make it suitable for various applications across different industries. In this article, we will explore the characteristics, properties, and applications of chlorinated polyethylene, shedding light on its importance and versatility in the world of materials science and engineering.

Characteristics and Properties of Chlorinated Polyethylene

CPE is obtained by replacing hydrogen atoms with chlorine atoms in high-density polyethylene (HDPE). It is available in the form of a white powder and is non-toxic and tasteless. The density of CPE typically ranges from 0.93 to 0.96 g/{cm}^3, with an average molecular weight of 5-25 million and a melt index of 0.01-2.0 g in 10 minutes. The degree of chlorination has a significant impact on the properties of CPE. For example, CPE exhibits plastic behavior when its chlorine content is less than 15%, behaves as a thermoplastic-elastomer when the chlorine content is between 16% and 24%, and transforms into a rubber-like elastomer with a chlorine content of 25-48%.

The addition of chlorine also affects other properties of CPE. Increasing the amount of chlorine enhances the oil resistance, air permeability, and flame resistance of the material. On the other hand, reducing the amount of chlorine increases the cold resistance and flexural strength of CPE. These variations in properties make CPE a versatile material that can be tailored to meet specific requirements in different applications.

Applications of Chlorinated Polyethylene
CPE finds extensive use as an impact modifier in polyvinyl chloride (PVC) formulations. It enhances the impact resistance of PVC products, making them suitable for a wide range of applications. Additionally, CPE is used in various other end-use applications, including:

1. Membranes
2. Wire and cable jackets
3. Automotive hoses and tubes
4. Coatings
5. Injection moldable parts
6. Extruded profiles

One of the key applications of CPE is as a shock corrector, primarily in PVC, accounting for close to 74% of global consumption in 2017. This highlights the significant role that CPE plays in improving the performance and durability of PVC-based products.

CPE is also utilized as a high-performance rubber or elastomer, either on its own or in combination with other rubber materials. It is commonly used in the production of wires and cables, hydraulic hoses, impact-resistant plastic strips and sheets, refrigerator sealing tapes, and magnetic cards. Furthermore, CPE serves as an additive in various plastic products, including rigid and semi-soft plywood profiles, pipes and fittings, ABS, and tires.

The filler used in the production of chlorinated polyethylene or CPE compounds primarily includes calcium carbonate, clay, or talc. These fillers contribute to the overall properties and performance of CPE-based materials, further expanding the range of applications for this versatile polymer.

Properties of Chlorinated Polyethylene (CPE)

CPE resins and their elastomers exhibit excellent physical and mechanical properties, including:

1. Resistance to various chemicals, oils, heat, and environmental conditions
2. Low-temperature performance
3. High compressive strength
4. Flame retardancy
5. High filler acceptance rate
6. Tensile strength
7. Abrasion resistance

These properties make CPE suitable for diverse industrial applications, where reliability, durability, and performance are essential requirements.

In addition to its physical and mechanical properties, CPE resins can vary from crystalline or rigid resins to flexible elastomeric products. This diversity allows for a wide range of applications across different industries, making CPE a highly sought-after material in the manufacturing sector.

Chlorinated polyethylene (CPE) is a versatile material with a diverse range of applications across various industries. Its unique composition and properties make it an ideal choice for enhancing the performance and durability of polymer-based products such as PVC, wires and cables, automotive components, and plastic goods. With its excellent physical and mechanical properties, CPE continues to play a crucial role in shaping the modern industrial landscape, offering innovative solutions to meet the evolving needs of different sectors.

In conclusion, chlorinated polyethylene stands as a testament to the ingenuity and adaptability of materials science, providing engineers and manufacturers with a valuable tool to create high-quality, reliable products that meet the demands of today’s dynamic market. As technology advances and new challenges emerge, CPE is poised to remain at the forefront of material innovation, driving progress and enabling the development of innovative solutions for a wide range of applications.

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