Know Your Materials: Polyethylene (PE)
Polyethylene (PE): A Versatile Thermoplastic with a Unique HistoryPolyethylene is a highly adaptable thermoplastic known for its range of uses. It was discovered by German chemist Hans von Pechmann in 1898, who accidentally created it while attempting to stabilize diazomethane. Industrial synthesis of polyethylene began in 1933 by Eric Fawcett and Reginald Gibson, with large-scale production of low-density polyethylene starting only six years later. Advances in catalyst technology during the 1950s revolutionized polyethylene production, resulting in the creation of high-density polyethylene, which has been a significant player in the manufacturing industry for over 20 years. Today, the annual production of polyethylene exceeds 100 million tonnes. Read on to learn more about this remarkable substance, including how it's made and its ideal applications.
Understanding Polyethylene: Properties and Production
Polyethylene is created through a polymerization process, which involves the distillation of hydrocarbon fuels into lighter monomer groups. These monomers are then combined with a catalyst to initiate polymerization. The most common method is coordination polymerization, which uses metal chlorides and oxides, but radical polymerization can also produce polyethylene.
Polyethylene comes in various types, grades, and formulations, each with unique properties. The most common types are branched, linear, and cross-linked polyethylenes. Low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE) are popular branched versions, while high-density polyethylene (HDPE) and ultra-high-molecular-weight polyethylene (UHMWPE) are popular linear versions.
Properties and Usage of Low-Density Polyethylene (LDPE)LDPE is a semi-rigid, thermoplastic material that is both flexible and durable. It is highly resistant to weathering, boasts high-impact strength, and is an excellent electrical insulator. Its unique flow characteristics make it particularly well-suited for creating shopping bags and plastic films. Despite its high level of ductility, LDPE has low tensile strength, which accounts for its stretchiness. However, this material's low resistance to heat and high flammability restrict its use in applications that involve high temperatures.
Understanding LLDPE: A Versatile Polyethylene CompoundLLDPE is a flexible polyethylene with excellent stress, crack, impact, and chemical resistance, as well as high impact strength. It is structurally similar to LDPE and can replace it in certain applications, but LLDPE has several benefits. It's possible to modify LLDPE's properties by adjusting the polymer formula, and it's less labor-intensive to manufacture than LDPE. This type of polyethylene is primarily used in film production.
Properties and Uses of High-Density Polyethylene (HDPE)Unlike LDPE and LLDPE, HDPE has a linear structure with minimal branching and enhanced rigidity. It's also flexible, weather-resistant, and can withstand low temperatures. HDPE is frequently used in outdoor furniture due to its excellent UV resistance and high tensile strength. Other common applications include plastic milk cartons, garbage bins, cutting boards, and laundry detergent bottles. However, HDPE is prone to stress cracking and has poor heat-resistance.
Manufacturing HDPE bottles.UHMWPE
Exploring the Benefits of Ultra-Dense PolyethyleneThis type of polyethylene is incredibly dense, even more so than HDPE. It can be woven into threads that are stronger than steel, making it a popular material for manufacturing high-performance equipment including bulletproof vests. With outstanding mechanical properties and high chemical resistance, it's ideal for use in the most challenging environments.
High-density cross-linked polyethylene (XLPE) is a durable material that is ideal for use in critical applications such as chemical storage pipework systems and high-voltage electrical cable insulation. It is resistant to hydrolysis, approved for potable water, and has excellent abrasion resistance and electrical properties.
Polyethylene Properties and Mechanical Specifications
Exploring the Properties and Drawbacks of Polyethylene
Polyethylenes are known for their exceptional chemical and impact resistance, excellent electrical properties, and low coefficient of friction. They're also lightweight, cost-effective, and easily machinable. However, the mechanical properties of polyethylene vary depending on the type. For instance, the mechanical specifications for LDPE are:
Tensile strength at 72°F: 1,400 psi
Tensile modulus: 57,000
Tensile elongation at break: 100%
Flexural modulus: 29,000 psi
Shore hardness (D): D45
It's important for product teams to be aware that polyethylene is toxic in its liquid form and can cause harm if inhaled or absorbed into the skin. Additionally, polyethylene isn't the most environmentally friendly material available. LDPE and HDPE are not very biodegradable, and since they're made from hydrocarbons and fossil fuels, they're not sustainable.
Why Choose Polyethylene?
The Versatility of Polyethylene: Why Engineers and Product Teams Choose this Commodity PlasticPolyethylene is a widely preferred commodity plastic by engineers and product teams due to its versatility and efficiency. It is cost-effective, readily machinable, and compatible with popular manufacturing techniques such as CNC machining and injection molding.Moreover, polyethylene is a top-performing plastic in terms of usage. It is a staple in consumer goods, ranging from containers to toys and films, and also has industrial applications, such as fuel tanks in the automotive industry, artificial joints in medical device manufacturing, and pipes and fittings.
Getting Started With Polyethylene Plastic
Partnering with Durasak Polythene Products means you'll be working with a team of experts boasting over 40 years of experience in flexible packaging and printing. We'll guide you through every step of the way, starting with selecting the ideal polyethylene plastic to suit your specific requirements. As stockists with both local and national partners, we're able to hold contract stock to ensure we meet your needs quickly. Ready to begin? Contact us today to get started.