How to Calculate Plasticizer

Let the power of infrared light calculate your plasticizer

According to ASTM international, infrared spectroscopy (IR spectroscopy) is a standardized way for calculating plasticizer content in a sample of plastic. Using a computer to compare the spectrum of a piece of plasticized plastic analyzed with an infrared spectrophotometer or spectrometer with a spectral library that includes various plastics plasticized with various amounts of plastizicers, you can calculate the amount of plasticizer that your sample contains. Infrared spectroscopy is a fast and nondestructive method for calculating plasticizer in your samples.

Things You'll Need

• Infrared Spectrometer
• Plasticizer spectral reference library database

Instructions

1. Prepare and place the sample into your infrared spectrometer for analysis according to your instrument's standard operating procedure. Ideally, if the spectrometer you are using is equipped for attenuated total reflection (ATR), very little sample preparation is required as you can press almost any size sample onto the ATR crystal.

2. Acquire the infrared spectrum of the sample using the infrared spectrometer's computer-based software. Again, this step should be performed according to the analyzer's standard operating procedure. A popular method is to take multiple scans of your sample and have the software compile an average of all the scans.

3. Compare the acquired infrared spectrum of your sample against that of the plasticizer reference spectral library. Based on the various the infrared wavelengths, the library will return "best matches" to your sample.

4. Calculate the plasticizer content of your sample by noting the characteristics of the best match from plasticizer spectral reference library. For example, if you have a plasticized piece of polyvinyl chloride and the best match in the library is a reference spectrum with a 30% plasticizer content, you can calculate your sample to have 30% plasticizer content.

Tips & Warnings

• The accuracy of calculating plasticizer with this method depends on several factors, chief among them is the power of your instrument and the size of your reference library. You should work with someone with experience using infrared spectroscopy to obtain the most reliable results.

• This method is also ideal for determining the type of plasticizer in your sample.

• Spectrometers use laser light. Always follow local safety policies when working with lasers in any instrument.

References

• ASTM Standard D2124-99, 2004, "Standard Test Method for Analysis of Components in Poly(Vinyl Chloride) Compounds Using an Infrared Spectrophotometric Technique," ASTM International, West Conshohocken, PA, 2003, DOI: 10.1520/C0033-03