Medical Chemical Compatibility
This Medical Chemical Compatibility Chart is a shorthand tool for describing the suitability of medical grade miniature fluidic and pneumatic component materials for use in contact with various chemicals. Use this chart to help guide your medical flow control component selection.
An Explanation of the Chemical Compatibility Chart Ratings
- A Excellent -- The component material is completely or almost completely inert when used with the specified chemical with negligible effect on mechanical properties.
- B Good -- There is some slight chemical effect on the component material that could create slight corrosion or discoloration but otherwise has minor effect on mechanical properties.
- C Fair -- The component material is partially affected by absorption of the specified chemical at the specified concentration and temperature levels and swelling may occur. The life expectancy of the component will be shortened and it is recommended that a different component material be used in these cases.
- D Poor -- The component material has no resistance to chemical attack by the specified chemical at the specified concentration and temperature and immediate damage may occur. Severe effects make this combination unsuitable for ANY use.
- N/A Unknown -- There is little or no technical information available for this combination of component material and chemical at this temperature and concentration. This combination has no recommendation and may require extensive testing and evaluation for its safe use.
How to use this chart to determine compatibility
Find the name of the chemical along the left column of the chart. The chemicals are listed alphabetically.
Compare the chemical with the various component material options listed along the top row of the chart.
Note the compatibility rating of the combination of chemical and component material and choose the best materials for sampling, evaluation and implementation.
Medical Grade Plastics
Medical grade plastics are made of high-purity resins that are compliant with FDA and USP Class VI material regulations and standards for biocompatibility. The formulations of medical grade plastics usually include additives that safely give them appropriate useful chemical resistance as well as making them more compatible with one or more sterilization techniques. Medical devices for human use made of medical grade polymers, colorants and other additives need to be tested. This is because the addition of colorants, processing aids and the use of the plastic in combination with other materials and adhesives can affect the biocompatibility characteristics of a medical grade resin.
Combinations of Chemicals
Chemical compatibility of component parts is extremely important because of possible rapid degradation and failure if the materials are not compatible with the environment where they are used or the chemical they are in contact with. Chemical compatibility is often compromised when handling more than one chemical or when handling compounds containing impurities. This listing does not provide information on chemical combinations.
Resistance to chemicals is a function of both temperature and concentration. There are many chemicals that can be safely handled only below a certain temperature. It is important to note all temperature references within this compatibility chart. All information provided in this chart is based on an assumed ambient temperature of about 70 °F (21 °C) unless otherwise noted. Mixing or dilution of certain chemicals as well as combinations of mixing and dilution of chemicals may cause undesirable chemical reactions including the production of heat that in turn can cause component failures.
Chemicals can affect the strength, flexibility, surface appearance, color, dimensions or weight of plastic components and component parts. The sorts of interactions that can take place between a chemical and a plastic are of three basic types: chemical attack on the plastic, stress cracking and physical change of the plastic such as softening and swelling.
Environmental stress cracking is the failure of a thermoplastic component when exposed to certain types of chemicals. This failure is not purely a result of chemical attack. A combination of three factors cause stress cracking: tensile stress, a stress cracking chemical and the inherent susceptibility of a thermoplastic to stress cracking. Stress cracking chemicals include detergents, surfactants, lubricants, oils, ultra-pure water and plating additives such as brighteners and wetting agents.
Relatively small concentrations of stress cracking agent may be sufficient to cause cracking. Chemicals that do not normally affect the properties of an unstressed thermoplastic may cause stress cracking under thermal or mechanical stress such as constant internal pressure or frequent thermal or mechanical stress cycles.
Interpretation of Chemical Resistance
The information in this chart has been supplied by reputable sources believed to be reliable and accurate. This information is to be used ONLY as a guide to selecting components for testing for appropriate chemical compatibility. Variations in temperature, concentrations, chemical combinations, durations of exposure and other factors may affect the performance of the component. Ultimately, the user must determine the suitability of the materials used. Before permanent installation, test the component with the chemicals and under the specific environmental conditions of your application. ISM does not warrant, neither express nor implied, that the information in this chart is accurate or complete or that any material is suitable for any purpose. It should be noted in the chart that the "A" rating does not mean or imply that the plastic material will perform within the original specifications.
Variations in chemical behavior during handling due to factors such as temperature, pressure, and concentration can cause equipment to fail even though it passed an initial test. Use suitable guards and personal protections when handling chemicals.