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Fourier Transform Infrared
Spectroscopy (FTIR) identifies
chemical bonds in a molecule by
producing an infrared absorption
spectrum. The FTIR generates an
infrared spectral scan of samples
that absorb infrared light. Metals
do not absorb infrared light, but
polymers that contain metals can
be scanned with FTIR.
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Fourier Transform Infrared
Spectroscopy (FTIR) identifies
chemical bonds in a molecule by
producing an infrared absorption spectrum. |
FTIR is important for screening,
and identifying polymer or plastic
samples. See below for Analysis applications
A material’s absorbance of infrared light at different frequencies produces a unique identification
based upon the frequencies at which the material absorbs infrared light and the intensity of those
absorptions. The resulting spectral scan is typically specific to a general class of material.
Example: Nylon scans have unique similarities but are definitively different than Polycarbonate
scans.
Unknown spectral scans can be analyzed to determine the base material of the unknown by comparing
their scan to spectral scans of known materials that are stored in a computer-based library
The resulting spectra produce a profile of the sample, a unique molecular “fingerprint” can be used to
easily screen and scan samples for many different components. FTIR is an effective analytical instrument
for detecting functional groups and characterizing materials.
Sampling Techniques Include; Transmission, solvent extraction, thin films, diffuse reflectance, and pressed
KBr pellets.
Samples the size of a single resin pellet can be scanned by reflective FTIR. Samples, which can be easily
tested by reflective FTIR, include polymer pellets, parts, opaque samples, fibers, powders, wire coatings,
and liquids.
An FTIR spectral analysis can easily identify classes of polymers such as Nylons, Polyesters, Polypropylenes, Polycarbonates, Polyurethanes, Acetals, or Polyethylenes.
FTIR spectral scan alone may not identify the type of Nylon, Pebex, or Polyester, identify a Polypropylene
or Acetal as a homopolymer or copolymer, or determine whether a Polyethylene is a high density or low
density material. Further identification using other analytical techniques is necessary.
FTIR Analysis Applications:
- Quantitative Scans
- Qualitative Scans
- Solids, Films, Liquids
- Organic Samples
- Inorganic Samples
- Plastics
- Polymers
- Contamination identification
- Impurities Screening
- Formulation, Deformulaation
- Packaging materials, foams, films, bubble wrap
- Medical devices, tubing, coatings, adhesives
- Personal care products, Cosmetics
- Consumer goods
- Toys
- Household products
- Building Products
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