ABOUT PLASTIC MATERIALS' CHEMICAL RESISTANCE

Buffers are an aqueous solution consisting of a mixture of a weak acid and its conjugate base, or vice versa. Its pH changes very little when a small amount of strong acid or base is added to it. Buffer solutions are used as a means of keeping pH at a nearly constant value in a wide variety of chemical applications. Generally, those in the life sciences and research will use buffers for molecular, protein, nucleic acid, and cell biology applications. These include cell culture, electrophoresis, ELISA, and chromatography processes.

The coordinating chart here details which popular plastic materials can hold their own against these commonly used buffers. Use this as a reference point for further researching which material might suit your application best.

Need a downloadable and easier to manage copy? Get our Life Science Compatibility Chart here! 

There are a few different ways to sterilize a plastic manifold including Autoclave, Dry Heat, Ethylene Oxide (EtO), Gamma Irradiation, and Electron Beam sterilization. To give a brief overview of each method:

AUTOCLAVE/STEAM STERILIZATION

Uses steam under pressure to sterilize components and parts. This process generates or injects steam into a pressure chamber between 250-300°F (121-148°C) at 15 psi.

DRY HEAT

Uses hot air to sterilize at significantly higher temperatures than autoclaving. This process makes it difficult to ensure the entire part reaches the necessary temperature for plastics with low thermal conductivity.

ETHYLENE OXIDE (ETO)

Uses a gaseous form of the sterilant to disrupt microbial DNA and their protein synthesis. Most use this process for plastics that cannot tolerate heat or radiation — commonly in single-use medical devices. This process often requires careful handling as the gas is flammable and poisonous.Because of the challenges associated with this method, it is more common for high volume sterilizations.

GAMMA IRRADIATION

Uses ionizing radiation to disrupt microbial DNA by exposing manifolds to gamma rays, typically from Cobalt-60.

ELECTRON BEAM STERILIZATION

Uses high-energy electrons to disrupt microbial DNA reproduction. It generates a higher dose rate than gamma irradiation, which means it has a lower exposure time and less degradation. However, this sterilization process has significantly lower penetrating power than gamma, making material density important.

We only state these as a brief primer. We strongly urge you to seek information from credible and reliable experts to get more in-depth understanding of each process. This also serves to give more foundational knowledge on which plastics can handle the sterilization process your product needs to withstand.

Here is a chart that we put together that shows which materials can handle which sterilization processes. We only mean for you to use this as a reference.

1: Radiation stable grades need to be used for radiation sterilization.

2: Require corrective tint to compensate for discoloration. Data courtesy of Industrial Specialties Mfg.