How Radiation Changes Kynar® PVDF in Strong-Ty® Cable Ties
Strong-Ty® cable ties are made from virgin Kynar Flex® 2850 PVDF. Understanding how this material responds to radiation helps customers evaluate it for sterile assemblies.
Arkema’s radiation crosslinking guide explains the molecular changes behind its performance.
What happens during crosslinking?
Radiation creates reactive sites along polymer chains. When neighboring chains connect at these sites, they form crosslinks—a network of chemical bonds.
These connections restrict chain movement. Crosslinking can increase strength and improve resistance to creep, the gradual deformation that occurs under sustained load. It can also reduce how far the material stretches before breaking.
How Kynar Flex® 2850 properties change
Arkema’s electron-beam testing shows several effects:
| Material property | Reported response |
|---|---|
| Tensile strength at break | Rises through 100 Mrad, then falls at 150 Mrad while remaining above its starting value. |
| Yield strength | Increases through 50 Mrad. |
| Elongation at break | Decreases overall, meaning less stretching before fracture. |
| Bending stiffness | Increases slightly through 20 Mrad, then decreases at higher doses. |
| Crosslinked fraction | Increases with radiation dose. |
| Melting temperature | Changes from 156°C before exposure to 155°C at 10 Mrad, 153°C at 20 Mrad and 146°C at 50 Mrad. |
These trends appear in Figures 7 and 9–12 and the melting-temperature table in Arkema’s guide.
A closer look at tensile strength
Arkema’s separate Kynar® PVDF Performance Characteristics & Data brochure provides the following ultimate tensile-strength results for Kynar Flex® 2850 in Table 8. These measurements used electron-beam exposure and ASTM D882 testing.
| Radiation dose | Equivalent dose | Ultimate tensile strength | Change from unexposed material |
|---|---|---|---|
| 0 Mrad | 0 kGy | 4,700 psi | — |
| 2 Mrad | 20 kGy | 4,700 psi | 0.00% |
| 4 Mrad | 40 kGy | 4,900 psi | +4.26% |
| 8 Mrad | 80 kGy | 4,900 psi | +4.26% |
| 20 Mrad | 200 kGy | 5,600 psi | +19.15% |
In this dataset, strength is maintained or increased at every reported dose.
What this means for Strong-Ty® cable ties
These data provide a useful foundation for understanding the Kynar Flex® 2850 resin used in our ties. The tensile-strength results offer a strong material basis for selecting Strong-Ty® for assemblies that undergo irradiation.
Your assembly deserves a cable tie selected for the demands of your process. Strong-Ty® combines virgin Kynar® PVDF, excellent chemical resistance, lot traceability and U.S. cleanroom manufacturing, with published resin data to support your material evaluation. Choose from 4″ Standard, 4″ Flex and 8″ Standard styles, then put Strong-Ty® to work on your next bioprocessing assembly. Order today or request samples to get started.
Sources
Arkema — Radiation Crosslinking of Kynar® PVDF Resins, particularly pages 3–5 and 9–12.
Arkema — Kynar® PVDF Performance Characteristics & Data, Table 8, page 10.