Category Archives: co-polyester
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.”
Understanding String: A Short Video
This short video will begin to open up the mystery and myths of tennis string.
Please add your comments and questions. We want to know what interests you so we can add it to our video and website activity.
Monofilament Material Comparison
Most monofilament tennis strings are polyester, a blend of polyester, or PEEK.
As you know, we believe there is no wrong string, just wrong applications. The graph will show the comparative stiffness of three (3) materials. The string is pulled at a rate of 1mm per second. The resultant spreadsheet for this particular test is about 5300 rows long.
With our spreadsheet, we have access to every mm of data. Maybe sometime we can post some of the individual data points.
Blast is polyester, V-Star is a unique blend of material (I do not know what it is), and MonogutZX is PEEK (polyetheretherketone).
The graph shows the cycle from 0 to 50 pounds three (3) times, then to failure (UTS). The quicker (shorter distance) the string reaches the 50-pound mark, the stiffer it is. MonoGut ZX did not fail in the 180mm excursion. You can see, in this case, the stiffer string fails at a higher force but shorter excursion.
Stiffer strings deliver less power and have a higher shock value. The midrange stiffness shows exactly what would be expected, and the softest string also indicates expected results.
String Shape
How’s the shape of your string?
Is it round, square, hexagonal, octagonal, triangular, or something else?
The string pictured here is square. The dimension across the flat sides is roughly .048 inches/1.22mm, which means the largest dimension is about .063 inches/1.6mm but due to the rounded edges it is less than that. The wear is happening on the “flat” side (.048/1.22),
A flat-sided string shape can create some issues when trying to achieve consistent string tension.
Side View of Fail
Flat Side Wear
String Bed View
This is expected because the string will want to align with the flat side, not the edges. This may cause the string to twist and create added friction when tensioning.
So, we can expect the “edges” to be exposed to the ball, and the “edges can create friction on the ball, which causes rotation!
Yea! How much and for how long is hard to know.
I believe it is safe to say “square” is a good “shape” for your string to be in for polyester monofilaments which we are looking at here.
Racquet Quest, LLC
