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# Choosing the best TPU for implantable medical devices
- URL: https://med-techinsights.com/choosing-the-best-tpu-for-implantable-medical-devices/
- Published: 2025-01-15T09:12:15.000Z
- Updated: 2026-10-22T07:56:06.000Z
- Description: Jennifer Green, Senior Global Technical Business Development Manager at Lubrizol Life Sciences discusses how to choose the best TPU for implantable medical devices. Thermoplastic polyurethanes (TPUs) are some of the most adaptable materials for medical devices, offering a balance between rigid polym
- Author: Oliver Johnson
- Tags: Insights, Medical Plastics, Materials

![](https://storage.ghost.io/c/98/19/9819191a-690e-400b-bf27-720adfd33f45/content/images/2026/10/10537-mti-website-square-image-10.png)

Jennifer Green, Senior Global Business Development Manager

#### ***Jennifer Green, Senior Global Technical Business Development Manager at*** [***Lubrizol Life Sciences***](https://www.lubrizol.com/Life-Science?ref=med-techinsights.com) ***discusses how to choose the best TPU for implantable medical devices.***

Thermoplastic polyurethanes (TPUs) are some of the most adaptable materials for medical devices, offering a balance between rigid polymers and elastomers. They’re customisable, resistant to wear and can transition from stiffness outside the body to softness inside, which improves patient comfort. They’re also great for catheters requiring thin walls, excellent strength and radiopacity.

TPUs are segmented block copolymers made of hard segments, containing isocyanates, and soft segments, containing long-chain alcohols (polyols). By selecting different chemistries for these segments—aliphatic or aromatic isocyanates for hard segments and polyether, polyester, polycarbonate or specialty polyols for soft segments—TPUs can be tailored to specific performance needs. Adjusting the ratio of hard to soft segments enables the creation of materials ranging from soft and flexible, approaching softness of silicones, to stiff and rigid for structural applications.

TPUs can be processed via extrusion, molding and thermal bonding techniques, but their flexibility doesn’t stop there. They are also compatible with solvent-based methods and 3D printing, giving manufacturers the tools to produce intricate designs and quickly prototype new devices.

**Choosing TPUs: Soft Segments**

The starting point for choosing the right TPU is to understand its use case—where in the body it will be located and the length of time it will remain there. This informs the optimal soft segment chemistry for biostability. For example, the choice of soft segment affects resistance to degradation, with polyether soft segment offering better hydrolytic stability than polyester soft segment.

Once this is understood, chemical resistance, strength and fatigue requirements help inform the choice of hard segments. Other factors, such as processing methods and visual criteria, including transparency, also play a role. By answering these questions, manufacturers can narrow down the chemistry to a few promising options for bench testing. It’s important to remember that enhancing one characteristic can affect others, so balancing these trade-offs through a structured decision matrix helps in arriving at the best solution.

For instance, material selection for long-term blood-contacting devices must address both physical durability and biological stability. Polyester-based TPUs are usually avoided because of their susceptibility to hydrolytic instability. Polyether-based TPUs provide better hydrolytic resistance but can be vulnerable to oxidative attack on the material surface, which may impact long-term performance depending on the device’s design and function. Known for their durability, polycarbonate-based TPUs offer excellent resistance to both hydrolytic and oxidative degradation.

Rigid materials demonstrate comparable performance trends. Polyether and polycarbonate-based TPUs offer significantly better durability in long-term blood-contacting applications than polyester-based TPUs. Polyether-based TPUs are the most stable option for devices exposed to low-pH environments such as long-term gastric implants. Polycarbonate-based TPUs, while offering strong oxidative and hydrolytic resistance, may be less suitable to such demands due to their vulnerability to hydrolytic attack in acidic conditions.

**Choosing TPUs: Hard Segments**

Aromatic and aliphatic TPUs each have their own strengths, giving medical device developers plenty to think about. Aromatic TPUs stand out for their toughness and chemical durability, providing roughly 20% greater tensile strength, fatigue resistance and abrasion resistance compared to their aliphatic counterparts. That said, they can yellow over time because their aromatic ring structure reacts to light, heat or radiation. While this discoloration requires additional design considerations for applications requiring long-term clarity, it doesn’t affect their overall performance. In fact, aromatic TPUs are a great choice for devices where strength and durability are the top priorities.

Aliphatic TPUs may be considered in applications where patient comfort and transparency are key, like vascular access and infusion devices. They resist yellowing, which means they stay clear and visually appealing even after extended use. Manufacturers also value their ease of processing when it comes to adding fillers, such as radiopaque materials, making it simpler to meet functional needs.

**Is TPU the right material?**

When selecting a TPU for your medical device, evaluate the following key factors:

- **Application:** What is the device’s purpose, and what specific functions will it need to perform?
- **Materials:** How do TPUs compare in terms of performance and compatibility to other materials being evaluated?
- **Body contact:** Will the device come into contact with blood, tissue or other body fluids?
- **Contact duration**: For how long must the material perform safely?
- **Physical criteria**: What are the strength, flexibility and durability needs?
- **Chemical criteria**: Must the device withstand body fluids or cleaning agents?
- **Thermal criteria**: Will it be exposed to high or low temperatures during use, sterilisation or transportation?
- **Sterilization**: Is the device intended for single use or will it be reprocessed?
- **Processing**: Does the material suit the planned processing techniques?
- **Visual properties**: Does the device require clarity or specific colour properties?
- **Radiopacity:** Is radiopacity necessary for imaging or diagnostic purposes?
- **Compliance**: Does the material meet the required industry and medical standards?
- **Material efficiency:** Is the material being evaluated available from the supplier in quantities aligned to your project’s scale and budget?

One of the key advantages of TPUs in medical manufacturing is the versatility in how they can be processed. Techniques like extrusion, moulding and thermal bonding make it possible to create thin, flexible, and durable tubing components which can be assembled into complex catheters. 

Solvent processing takes advantage of TPU versatility by dissolving the material into a liquid form, allowing for precise shaping and coating. As the solvent evaporates, the TPU remains in its finished shape. This technique is especially useful for creating fine details or thin, consistent coatings that other processes can’t easily replicate. It can also be used to incorporate thermally sensitive ingredients that might further enhance the device’s performance.

TPUs aren’t just versatile—they’re a breakthrough material for implantable medical devices. The beauty of TPUs is how easily they can be adapted to fit different applications. OEMs and material manufacturers have an opportunity to work together to fine-tune their chemistry and performance traits to meet the most demanding medical device performance requirements.