Category Archives: Polyester
Soft is the New Black!
The word “soft” is popping up everywhere; for good reason, we think!
Most juniors and high-level players we deal with have or are now switching to “softer” strings.
The following plot shows the difference between Luxilon Element 125 and Luxilon Element IR Soft 127. Looking at the slope, you can tell the Soft is softer than the non-soft, but by how much?
Element v Element Soft
A quick calculation says about 12.3% at 50 (22.68Kg) pounds of force. If you follow the slope, you will see that at 100 pounds of force (45.36Kg) the strings intersect at a deflection of 54.8mm.
If you hit very hard and exceed the 100-pound mark, the “soft” will become slightly less soft than the “non-soft.”
So, what’s the big difference?
For nearly twenty years (20) years, we have been using PEEK for high performance tennis strings. Ashaway has been using PEEK longer than we have under MonoGut ZX and ZX Pro (thinner) models.
“The significant property differences between 1.25mm polyester and 1.25mm polyetheretherketone (PEEK) are based on their chemical composition, mechanical strength, thermal resistance, and durability. Here’s a comparison:
- Chemical Composition
- Polyester: A polymer made of ester functional groups commonly used in textiles, films, and some industrial applications.
- Polyetheretherketone (PEEK): A high-performance engineering thermoplastic with ether and ketone groups, known for its superior mechanical and thermal properties.
- Mechanical Properties
| Property | 1.25mm Polyester | 1.25mm PEEK |
| Tensile Strength | Lower (~50-100 MPa) | Much higher (~90-120 MPa) |
| Elastic Modulus | ~2-4 GPa | ~3.6-4.0 GPa |
| Toughness | Flexible, lower toughness | High toughness, impact-resistant |
| Abrasion Resistance | Moderate | Very high |
- Thermal Properties
| Property | 1.25mm Polyester | 1.25mm PEEK |
| Melting Point | ~250°C | ~343°C |
| Glass Transition | ~70°C | ~143°C |
| Thermal Stability | Moderate | Excellent |
PEEK can withstand much higher temperatures than polyester, making it ideal for high-heat applications.
- Chemical Resistance
- Polyester: Moderate resistance to chemicals but degrades in strong acids and alkalis.
- PEEK: Excellent chemical resistance, even to strong acids, bases, and solvents.
- Electrical Properties
- Polyester: Good dielectric properties but lower breakdown strength.
- PEEK: Exceptional electrical insulation properties, making it suitable for high-performance applications.
- Water Absorption & Durability
- Polyester: Absorbs some moisture, reducing strength over time.
- PEEK: Extremely low water absorption, maintaining strength and dimensional stability.
- Applications
- Polyester: Used in textiles, packaging, and some low-load industrial applications.
- PEEK: Used in aerospace, medical implants, and high-performance engineering applications.
Conclusion
If you’re looking for high strength, thermal resistance, and durability, PEEK is far superior to polyester. However, polyester is more cost-effective and widely used in consumer applications. The choice depends on the required application and performance needs.”
A Hybrid View…Part 2
Let’s Look at a Hybrid Graph
A client asked, ” Would putting natural gut in the cross string instead of the main string create a softer string bed?”
That question is the precursor to the graph below, so I will let the video tell the story.
This graph does not reflect the stiffness of polyester string. So, in any format, a natural gut may help soften the string bed if polyester is used.
Racquet Quest, LLC
