Have you noticed stress cracking in polycarbonate parts that contact flexible PVC for prolonged periods?
As it so happens, this doesn’t only happen to polycarbonate. Other commonly used medical rigid polymers, such as ABS, polystyrene, and acrylic, can exhibit the same phenomenon. All of the aforementioned materials are valued for their strength, clarity, and long history of safe use in medical applications; however, each can succumb to failure because of plasticizer migration from contact with flexible PVC.
Flexible PVC is the most common material used to manufacture clear flexible tubing for medical applications. The interaction between the plasticizer in flexible PVC compounds and the surface of most rigid engineering plastics parts can lead to reduced physical properties and, in some cases, catastrophic failure of the rigid plastic part.
This whitepaper explains the cause and impact of plasticizer-induced stress cracking, as well as the relative stress crack-resistance of specialty-formulated rigid PVC versus polycarbonate (et al) when exposed to PVC plasticizers commonly used in PVC medical tubing applications.
For part design or processing considerations, we also test the impact of stress – which may occur as a mechanical force placed on the part while in service, or as residual stress embedded into the plastic part during its fabrication.
This paper is appropriate for any maker of medical devices that requires medical tubing.
