Logo UHasselt





Logo UHasselt Universiteit Hasselt - Knowledge in action



Bruker Vertex 70 spectrometer with DTGS detector

FT-IR spectroscopy is a NDT technique for identification of unknown polymers, resins, rubbers, residues and inorganic compounds such as asbestos.
FT-IR is part of electromagnetic radiation between 12700-10 cm-1.  Mid-IR ranges between 4000-480 cm-1.
Interaction between matter and IR radiation occurs when the dipole moment changes during the vibration within a chemical bond.  Different bonds and functional groups will result in IR absorptions at different wavelengths or wave numbers.  The resulting IR spectrum can be considered as a fingerprint of the molecule or material.  FT-IR spectroscopy can offer information on the different functional groups within a material.
IR measurements can be performed as well for solids, liquids and gasses.
FT-IR spectra can be obtained in transmission; liquids can be applied as a droplet between two windows and measured directly as a thin film (KBr, NaCl).  Solids can be measured directly (ATR); powders can be analyzed by mixing with KBr, pressurized to KBr pellets before analysis or ATR (ATR). Polymer pellets can be pressed to thin foils for transmission measurements or can also be measured directly (ATR).
Different accessories are available for direct analysis or surface analysis.  Accessories can be introduced directly in the sample compartment.

ATR FT-IR spectroscopy (Attenuated Total Reflection)

PIKE ATR accessory    Spectra Tech
Horizontal ATR FT-IR spectroscopy      Spectra Tech
Micro-vertical ATR FT-IR spectroscopy      Spectra Tech

The sample (sheet, film, powder) is pressed on to ATR crystal (Ge, ZnSe, diamond).  Multiple internal reflections occur.  The penetration depth (0-2 µm) is depending on the angle of incidence and difference in refractory index between ATR crystal and sample.
For grazing angle a GATR accessory can be used.
This technique is suitable for analysis plastics, powders, rubbers, residues, coatings, adhesives, multilayer, asbestos.

Specular reflection   Spectra Tech
Transparent coatings applied on high reflecting surfaces can be analyzed by specular reflection.

Diamond anvil cell   Specta Tech
A diamond anvil cell contains two conical diamond parts where small particles (e.g. paint particles) or elastomers, plastics can be squeezed so that thin transparent layers are obtained for FT-IR micro-analysis in transmission.

Typical applications

  • Identification of resins, residues, plastics, rubbers, adhesives
  • Identification of coatings
  • Characterization of defects in coating
  • Evaluation of degreasing processes
  • Study of adhesive failure
  • Compound analysis using FT-IR analysis
  • FT-IR analysis of plasticizers and filter materials in plastics

FT-IR microscopy

Bruker Vertex 70 FT-IR spectrometer equipped with Hyperion FT-IR microscope with MCT detector.
FT-IR analysis of micro samples (20-300 µm) in transmission, reflection and ATR mode is possible using a FT-IR microscope.
Locations are selected using the IR microscope as a light microscope or using the built-in video camera.
The FT-IR microscope has a dedicated MCT detector.  Micro ATR FT-IR analysis is also useful for line scanning in multilayer specimen or for the study of cross sections.

Typical applications

  • FT-IR analysis of residues in micro-electronic devices
  • Adhesion failure analysis
  • Characterization of defects and inclusions in coating
  • Micro spot identification using micro extraction techniques
  • Evaluation of the chemical functional groups on reflecting and non-reflecting surfaces
  • Evaluation of cleaning techniques
  • Study of material failures at interfaces
  • Kinetic studies as function of temperature
  • Analysis of asbestos fibers
  • Analysis of multilayer materials
  • Analysis of particles in nozzles, filters during processing