Blog

Polyethersulfone (PESU) stands at the forefront of advanced engineering thermoplastics, captivating industries with its remarkable properties and diverse applications. A high-temperature amorphous polymer, PESU has become a stalwart choice where conventional engineering plastics fall short. In this exploration, we delve into the intrinsic characteristics and versatile applications that define polyethersulfone, unraveling the essence of this extraordinary material.

1. What is polyethersulfone?

Polyethersulfone (PESU) is a transparent amorphous resin, often abbreviated as PESU or PES, belonging to the high-performance thermoplastic family known as polysulfone. PESU is produced through polysulfonate or polyester synthesis. It consists of mainly aromatic rings (phenyl and biphenyl groups) linked alternatively by ether and sulfone groups.

Developed by ICI UK in 1972, PESU resin stands as a comprehensive thermoplastic high polymer material. This advanced engineering thermoplastic boasts excellent transparency, and flame resistance, and stands out as one of the least smoke-emitting materials, making it a notable choice for high-temperature applications.

Its amber appearance distinguishes it, and it has become one of the most widely utilized special engineering plastics. PESU resin offers a versatile range of properties and can be processed into granules and powder of various sizes, catering to diverse manufacturing needs. This innovative material finds extensive applications in different industries due to its remarkable characteristics and adaptability.

Read more: What is thermoforming? The process and applications

2. What are the properties of polyethersulfone?

Chemical structure of polyethersulfone

 

2.1. Heat resistance

Polyethersulfone exhibits higher heat resistance and rigidity compared to polysulfone. This material has exceptional creep resistance and dimensional stability under high temperatures. Its thermal deformation temperature is 203℃, glass transition temperature is 225℃, and UL temperature is 180℃. PESU maintains mechanical properties up to 200℃ in continuous use.

2.2. High mechanical property

PESU ranks high among thermoplastics in terms of mechanical properties. Tensile strength is 84.3MPa, flexural modulus is 2.65GPa, breaking elongation percentage is 5-6%, and notched impact strength is 91J/m.

2.3. Chemical resistance

Resistant to gasoline, engine oil, lubricating oil, freon, and cleaning agents, PESU boasts the best resistance to solvent cracking among amorphous resins. However, it is susceptible to dissolution in polar solvents like chloroform and acetone.

2.4. Impact resistance

PESU matches the impact resistance of polycarbonate without notches. The impact strength is influenced by the radius of the notch, with smaller radii leading to lower impact strength.

2.5. Stable insulating property

PESU demonstrates excellent insulating performance, remaining stable under temperatures up to 200℃.

2.6. Good processability

Compared to polysulfone, PESU offers superior fusion processability and lower melt viscosity, with a molding shrinkage of only 0.6%.

2.7. Creep resistance

Characterized by a small linear expansion coefficient and low-temperature reliability, 30% glass fiber reinforced PESU resin maintains properties similar to aluminum at temperatures up to 200°C.

2.8. Hydrolysis resistance

PESU exhibits excellent resistance to hot water or steam at temperatures ranging from 150 to 160℃, and it remains eroded by acids and bases even at high temperatures.

2.9. Non-toxicity

Polyethersulfone is an FDA-approved safe material, meeting the requirements of JMHW Announcements No.434 and No.178.

2.10. Flame retardant

PESU demonstrates self-extinguishing properties, achieving up to UL94V-0 grade flame retardancy without the addition of flame retardants.In summary, polyethersulfone (PESU) emerges as a multifaceted material, combining heat resistance, mechanical strength, chemical endurance, and various other properties that make it a preferred choice in diverse industrial applications.Read more: Top high heat plastic materials for engineering applications

3. Limitations of polyethersulfone and ways to optimize production efficiency

 

Polyethersulfone has some limitations needed to optimized production

While polyethersulfone (PES) offers impressive performance properties, it comes with certain limitations that warrant attention:

• High cost and high sales price: PES is associated with a very high production cost, making it suitable only for highly demanding applications where its exceptional properties are crucial. PES faces a drawback in terms of a very high sales price compared to other engineering thermoplastics like polyamides, polyesters, and polycarbonates.
• High-temperature and pressure processing: The polymer requires processing at elevated temperatures and pressures, which may pose challenges in terms of energy consumption and equipment considerations.
• Susceptibility to polar solvents: PES is susceptible to attack by polar solvents such as ketones, chlorinated solvents, and aromatic hydrocarbons, limiting its use in environments with these substances.
• Low UV resistance: PES exhibits low resistance to UV light, which can impact its performance in outdoor or sunlight-exposed applications.
• Low-stress crack resistance: Being amorphous, PES has low-stress crack resistance, especially when exposed to organic solvents.

Due to these limitations, PES applications are currently restricted to highly sophisticated small-volume areas in industries such as electronics, aerospace, and medical.

To optimize production efficiency and address these limitations, blending high-performance PES with other engineering thermoplastics presents a viable solution. This approach can enhance processability and improve chemical properties, potentially leading to a significant reduction in the overall production cost. Blending PES with polycarbonate (PES/PC) results in materials with good flow properties and mechanical performance similar to neat PES. However, there is no improvement in chemical resistance due to the amorphous nature of PCs.

Additionally, polymer alloys of PES with polyamides (PES/PA) demonstrate improved flow, enhanced toughness, and a stable morphology. The semi-crystalline nature of polyamides contributes to significantly higher chemical resistance compared to pure PES. These advancements have facilitated the penetration of PES into larger volume applications, overcoming some of its inherent limitations.

4. Applications of polyethersulfone

 

Polyethersulfone filter

Polyethersulfone (PESU) has gained significant traction across diverse industries. Here are key applications highlighting the material's wide-ranging utility:

4.1. Automotive advancements

• PESU resin, reinforced with glass or carbon fibers, replaces traditional metal and thermoset materials in automotive components.
• Widely used under the hood for battery caps, oil pumps, transmission parts, bearing cages, and ignition components.
• It has applications in car headlights, including screens, housings, reflectors, and engine oil circulation systems due to its high-temperature resistance.

4.2. Electrical and electronic components

PESU's high stiffness, strength, and dimensional stability make it suitable for various electrical and electronic applications.

• Used in coil formers, connectors, injection-molded printed circuit boards, parts for power circuit breakers, and lamp holders.
• Applied in TV components, hair dryer parts, oven components, and other electrical appliances requiring thermal and dimensional stability.

4.3. Industrial utilization

• Preferred in industrial applications where performance surpasses conventional engineering plastics like polyamide.
• Commonly used in pumps, valves, oil level indicators, heat exchanger parts, and components for automatic beverage dispensers.
• Applied in the manufacturing of seals, conveyor belt idlers, and packing for absorption and distillation columns.

4.4. Medical innovations

PESU is used for medical equipment

• PESU withstands cold sterilants, disinfectants, and germicides, making it suitable for medical applications.
• Widely used in membranes for dialyzers, surgical instruments, sterilizing boxes, infusion equipment, and reusable syringes.
• Offers outstanding resistance to gamma and electron beam radiation, making it suitable for applications requiring repeated sterilization.

4.5. Membrane technology

PESU is a common polymer in commercial membrane fabrication, creating strong, microporous film asymmetric membranes. These membranes efficiently remove particulates during general filtration, maximizing the recovery of critical drugs. 

5. Processing methods for polyethersulfone (PESU)

Polyethersulfone (PESU) offers versatility in processing through various conventional thermoplastic methods, ensuring its adaptability to diverse applications:

5.1. Injection molding

• Temperature recommendations: PESU is amenable to injection molding with recommended barrel temperatures ranging from 340-380°C and melt temperatures of 360°C.
• Mold temperatures: Ideal mold temperatures fall within the range of 140-180°C, with higher temperatures potentially required for thin-walled molding.
• Shrinkage characteristics: Unfilled PESU exhibits low shrinkage, making it suitable for molding small parts with tight dimensional tolerances.
• Special considerations: For very small parts, PESU's low linear shrinkage is advantageous.

5.2. Extrusion (film/sheet/tube)

• Temperature range: Extrusion of unfilled PESU can be carried out at temperatures between 340-390°C.
• L/D ratio: A recommended L/D (length-to-diameter) ratio of around 20 is suitable for extrusion processing.
• Elasticity and orientation: PESU generally exhibits high elasticity, resulting in weak orientation during extrusion processes.

Polyethersulfone's adaptability to injection molding, extrusion, blow molding, and thermoforming processes, combined with its low shrinkage and dimensional stability, makes it a versatile choice for manufacturing a wide range of components across industries. The recommended processing parameters ensure efficient and reliable production of PES-based products.

6. Conclusion

In conclusion, Polyethersulfone (PESU) emerges as a cornerstone in the realm of high-performance polymers. Its exceptional heat resistance, dimensional stability, and adaptability to various processing methods position PESU as a go-to material across automotive, electronics, medical, and industrial sectors. As industries continue to seek innovative solutions, Polyethersulfone remains a beacon of reliability, pushing the boundaries of what's achievable in the world of advanced polymers.

Please visit the EuroPlas website regularly to learn the latest and most useful information about different types of plastic materials. If you are looking for engineering plastic compounds, environmentally friendly bioplastics, plastic additives, filler masterbatch, color masterbatch, etc, don't hesitate to contact us immediately for support and the best advice.