FTIR testing, more correctly known as Fourier Transform Infrared Spectrometry, uses infrared light to create a spectral analysis. This spectral analysis can then be used to determine if there are any copolymers (made by the reaction of different monomers), or the presence of various additives and resins.
It is possible to complete FTIR testing on a wide variety of different types of materials. It can be used to identify a solid, gas or a liquid, which makes it an effective type of test for both known and unknown materials.
For known materials, it can be used to see if there are any impurities or contaminants in a sample. With unknown materials the absorption or the transmission of the infrared through the material can be compared to the spectral analysis of known materials, clearly identifying the components.
The name is actually derived from the use of the Fourier transform, which is a mathematical formula that measures how a signal breaks down into the underlying frequencies over time.
There are different types of FTIR testing used on different materials. There can be far-infrared, mid-infrared and near-infrared FTIR. Testing of polymers falls into the near-infrared FTIR category.
This testing process is extremely accurate and can be completed rapidly with very good levels of sensitivity, able to identify even minute materials with a polymer or that make up a resin or composite. Highly effective, this is a recommended testing option for many different applications.
Another type of near-infrared FTIR is the specialized TG-IR or thermogravimetric analysis infrared spectrometry. This test includes heating up the sample material and measuring the gas that is emitted. Comparing this to the original sample material can provide information on the components based on the weight loss at different times during the heating process.