Few crises have galvanised the industrial world in the way that the current Covid-19 pandemic has done. As more was known about the illness, countries across the world became aware that their capacities for and inventories of key medical equipment was sorely lacking. While face masks and PPE equipment have been relatively easy to scale up quickly, the more high-end and complex medical equipment has required an even larger push to ensure we have the numbers needed to confront the situation at hand.
With urgency being the need of the hour, the manufacture of ventilators has spiked across the world. In India, the government has approached various private contract manufacturers to divert capacity to the manufacture of ventilators. A plan to build a moving, railway hospital with 20,000 beds is said to be materialising, while key states have set up Covid-centric hospitals to ensure that they have sufficient capacity. Considering that roughly 5% of cases end up requiring hospitalisation, the demand for ventilators is, at present, insatiable.
High-performance polymers have always been at the forefront of medical device manufacturing. Recently, both PEEK and PPSU have gained some attention for their application on ventilator manufacture.
Here we look at some of the key properties of these polymers and how they lend themselves to the manufacture of ventilators and other medical devices.
Biocompatibility – different readily available grades in PEEK and PPSU offer biocompatibility. However, it should be noted that biocompatibility varies. Some medical grades are acceptable for use only in equipment and devices that will not come in contact with human skin. Still more specialised grades are suitable for human contact, while the most high-end grades might be used inside the body.
FAD approval – most graded of PEEK, PPSU, PTFE, and even PVDF come pre-approved by the FDA. This means that for some medical applications, no further certification may even be needed. It is beneficial in a time like this, where the need to fast-track development is key.
Low particle discharge – one of the key requirements of a material that is used in the medical space is that it needs to exhibit minimal particle discharge. It is common for many filled grades of polymers to exhibit high levels of discharge. This discharge can settle in other areas of the equipment and cause both mechanical and electrical problems within the device. Furthermore, for respirator devices, the chance of particles entering the human lung would be very detrimental indeed!
Both PEEK and PPSU are known for being very stable in this regard. Data released by NASA shows that the total percentage of mass lost over the lifetime of the part is only 1.1% and 0.3% for PPSU and PEEK, respectively.
Flammability – most polymers, including PEEK and PPSU conform to at least a V-0 rating on flammability, meaning that even with the application of a flame, the material will self-extinguish within 10 seconds once the flame is removed. This is a critical feature from the point of view of safety.
Mechanical strength – aside from the chemical and medical compatibility, both PEEK and PPSU exhibit superior mechanical strength. PEEK has one of the highest tensile strengths among polymers. As a result, the loads and wear that the parts are able to take are unparalleled and yield a long-lasting solution.
Machinability – once of the key issues during the pandemic has been time-to-market. There is very little time to engage in extensive R&D and even trials need to be conducted with a very quick turnaround in mind. The fact that PEEK and PPSU can be machined, moulded, and even 3D printed makes their application that much more beneficial to the current climate. While initial prototyping can be done using 3D printing or machining, the production can gradually shift to moulding once the dimensions are frozen and the mould is developed. Since mould development can sometimes take weeks, the machinability of PEEK and PPSU serves as an intermediary measure to ensure that parts are supplied in the short term.
There are a host of polymer solutions available in addition to PEEK and PPSU. As things proceed, there is no doubt these too will find their uses. Such is the nature of the pandemic that new applications, advantages, and properties are constantly being discovered.