Modified PEBA & TPU Compounds Deliver Superior Hydrolytic Stability for Medical Catheters

Clariant Plastics & Coatings Healthcare Polymer Solutions, in partnership with a leading medical‑device manufacturer, has finalized the development and rigorous testing of novel thermoplastic compounds engineered to withstand hydrolytic degradation caused by high humidity and temperature. This breakthrough is particularly vital for resins that incorporate high loadings of radiopaque metals, as such fillers amplify degradation risks.

Marketed under Clariant’s Mevopur brand, the modified PEBA (polyether block amide) and TPU (thermoplastic polyurethane) formulations were first unveiled at MD&M West 2020 and are poised to enhance the performance and safety of medical catheters.

Catheters are typically fabricated from soft, flexible polymers like PEBA or TPU, often reinforced with metallic fillers—tungsten or tungsten carbide—to provide radiopacity for X‑ray fluoroscopy. According to Steve Duckworth, global head of marketing & business development, prolonged exposure to heat and moisture breaks the polymer chains that underpin critical mechanical properties, jeopardizing device function and patient safety. Even trace moisture trapped on the polymer surface, fillers, or pellets can trigger these hydrolysis effects.

The new Mevopur technology combines proprietary processing methods with specialized additives that confer hydrolytic resistance. Accelerated aging tests on both extruded tubing and injection‑molded samples demonstrate markedly superior performance versus unmodified materials.

One key indicator of polymer scission is a rise in melt flow index (MFI), reflecting reduced viscosity as chains shorten. Over a 26‑week period, the MFI of a standard 74% tungsten‑filled PEBA Shore 35D compound increased sharply, becoming unmeasurable after four weeks. In contrast, the Mevopur variant maintained an almost unchanged MFI throughout the test. The disparity intensified when tungsten‑carbide fillers were used.

Tensile‑test bars molded from the same materials revealed that unmodified samples lost 20–25% of their tensile strength and elongation, whereas Mevopur samples retained nearly 100% of their original properties. The effect was even more pronounced with tungsten‑carbide‑filled formulations.

"The ultimate reliability of catheter components hinges on the stability of polymer properties under diverse conditions," says Duckworth. "Our data confirm that the Mevopur radiopaque compounds substantially mitigate hydrolytic degradation, restoring predictability and underscoring the value of long‑term collaboration between device manufacturers and material suppliers like Clariant."

Clariant produces Mevopur concentrates and compounds at its EN:ISO13485‑2016 certified facility in Lewiston, Maine, and across a global network of ISO13485 sites in Europe and Asia. The Healthcare Polymer Solutions team develops products ranging from PE to PEEK using USP Class VI, ISO10993‑pre‑tested ingredients. For over a decade, the Mevopur portfolio has encompassed PEBA, TPU, nylon 12, and various radiopaque fillers, with fluoropolymers recently added.