Polymer Analysis

General Techniques for Obtaining Infrared Spectra for Qualitative Analysis

Purpose: Identification of chemical structure and functional groups of polymers, and comparison of unknown samples with reference materials to verify polymer type and composition.

Standards:

ASTM E1252, ASTM D3677

Measured Properties

• Functional Groups:
  Identification of chemical groups present in the polymer chain, such as –OH, –COOH, –C=O, –CH₃, –CH₂–, etc.
  Displayed as absorption peaks in the IR spectrum.
• IR Absorption Spectrum:
  Graph of infrared light absorption versus frequency or wavenumber (cm⁻¹).
  Provides qualitative information about the type of bonds and polymer structure.
• Reference Spectrum Comparison:
  Comparison of the spectrum of an unknown sample with that of known reference materials to determine the polymer type.
• Peak Intensity and Position:

Intensity of peaks indicates the density or concentration of functional groups.

Position of peaks is used to identify bond types and chemical structure.

• Additives / Fillers Detection:
  Identification of the effects of additives, pigments, or fillers in the IR spectrum.