Article By SABIC Innovative Plastics
There are various items that can effect how a plastic part will perform in a particular application. One of the key factors, and sometimes over looked, is the chemical compatibility of the plastic resin. Thermoplastics chemical compatibility is dependent on a number of criteria, including time, temperature, molded-in stress, and any external stress to which the part is subjected in a given application. Chemical exposure ordinarily results in a softening effect, or cracking and crazing of the thermoplastic. As softening occurs, the percent weight increases while tensile strength decreases. As cracking and/or crazing occurs, the percent elongation decreases. In general, amorphous polymers tend to be highly viscous and more susceptible to chemical attack than crystalline polymers, which typically are low viscosity and easier-flowing materials. Parts molded of crystalline resins will typically be lower stressed and more chemically resistant. Most products, whether a hand-held electronic device or a product designed to sit on top of your desk, require resistance to the chemicals they can potentially come in contact with during every day use. The proper design of a part as well as the proper material selection, including its chemical compatibility, are critical to the success of the part’s performance.
SABIC Innovative Plastics has tested many of its resins against various types of chemical agents, including cleaning fluids, oils, adhesives, etc. The Engineering Data & Tools, within the SABIC Innovative Plastics website, is where you can find the Chemical Compatibility data. A search can be performed by selecting a chemical agent or material. Once a chemical agent or specific resin has been selected, the results of the potential chemical compatibility are shown in terms of % property retention of the resin after exposure to the chemical or specific condition. The data is reported in a color-coded format to show the level of potential compatibility with the chemical and the conditions under which it was tested. The color green is indicative of compatibility where 90% or greater tensile strength is retained, yellow is considered marginal with 89% to 80% tensile strength retention, and red is indicative of tensile strength below 79%. The % elongation is also measured and color-coded with green in the range between 139% to 80%, yellow from 79% to 65%, and the color red with elongation values above 140% or below 65% after exposure to the chemical agent / condition. The test conditions and the sample conditioning are also shown to provide additional information. Although many of the SABIC Innovative Plastics resins have been tested for a variety of chemical agents, it is not a complete listing of all possible chemical agents. Please note that SABIC Innovative Plastics’ chemical compatibility data is a guide that does not guarantee specific results. Actual end use testing should always be conducted on the part to confirm whether the material is suitable for a particular application and its end use environment.
In conjunction with this Chemical Compatibility tool, there are several new material search tools on the SABIC Innovative Plastics website for users to find a material based on specific properties, or to search for an alternative material. These new material search tools are enabled by IDES and can also be accessed through the Build My Application page, where many engineering tools have been made available for design and application support.
Registration on the website is required to access the chemical compatibility data and material search options.
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