In the plastics and polymers business, there are a number of scenarios where getting immediate and reliable answers is vital:
- You need to verify incoming raw materials (and the dock is backing up)
- An extruder line shuts down because of uncertainty in a resin or additive
- Your contract lab is backed up for weeks
- A customer rejects a shipment
- Your flagship product gets a bad knock in a trade publication, and you need to know why
Fourier-transform infrared (FTIR) spectroscopy
Fourier-transform infrared (FTIR) spectroscopy is the go-to technique for rapid identification of polymer compounds. In fact, the development of FTIR parallels the development of the plastics and polymers–from the chemistry lab to prototyping to production and shipment.
At its core, FTIR is a fingerprinting operation. Instrument owners develop or purchase a long list of compound spectra stored in a database. As new materials come online, new compounds can be added to the database. Then, when an incoming or unknown sample arrives, the FTIR operator can quickly use the chemical “fingerprint” of the sample to correlate it to a compound in the database. In addition to efficiently verifying incoming raw materials, FTIR may be instrumental in flagging a contaminant in the material, identifying a formulation mistake, or troubleshooting adjustments to process conditions in production.
Challenges of FTIR analysis
This sounds simple, but unfortunately things can get a little tricky. All spectroscopies are essentially theoretical, and sometimes the matching process may lead to uncertainties. Two very similar, but functionally unique, compounds may exhibit nearly identical spectra. The material you’re analyzing may not be a pure as the reference sample in the database.
How to get the best spectroscopic analysis
How can you be sure you’re getting good FTIR matches of polymers and additive materials? One route may be to buy the best, most expensive FTIR spectrometer on the market. In the end, you’re buying a Swiss-Army™ knife because it has one good blade. Your better move is to get a good, fixed range desktop spectrometer with great optics and budget-friendly price tag. Then the next step is to get great FTIR software that makes identifying unknowns, contaminants and process chemistry 100% reliable.
Our newest desktop FTIR spectrometer, the Thermo Scientific™ Summit™ FTIR Spectrometer includes a “QCheck” routine that makes it easy for users to compare one spectrum to one or more reference spectra. Owners create a “Workflow” that fits their analytical requirements (or we can help you set up the workflow).
Spectroscopic analysis software
Based on the materials you routinely inspect, you designate the best spectral region for the application, choose the spectral resolution, and determine how much signal averaging is required to produce an acceptable spectrum for a Pass/Fail with no chance for error or process deviation. Once set up, operators can use the Workflow to run multiple samples, saving results in a spreadsheet file.
To automate the process further, FTIR software on the Nicolet Summit helps you to automatically create workflows based on your spectral processing history. The more you run, the smarter it gets. Now you can use a foolproof workflow that enables operators of any skill set to run the instrument.
To demonstrate the ease and reliability of the FTIR software on the Nicolet Summit Spectrometer, scientists here overlaid the polystyrene reference material and an unknown plastic sample. Visually, the two spectra look similar. The peak locations and intensities were strongly overlapped. However, the results of the QCheck analysis showed a match value of 99.81, which is about as close to foolproof as you’ll get with any FTIR.
See for yourself. Download “Verify Samples Quickly — Using multiple reference samples with an automated workflow”
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