Introduction to FTIR Spectroscopy
📌 This video focuses on the basics of Fourier Transform Infrared Spectroscopy (FTIR), a critical test method used by material analysts in the plastics industry for problem-solving.
🔬 FTIR provides a graphical representation (like a fingerprint) of a material's chemical composition, most useful for organic liquids and solids.
📚 The goal is to equip viewers with the basic concepts of FTIR, expected results, and understanding how to interpret them for material identification.

How FTIR Works and Result Presentation
💡 FTIR involves exposing the sample to infrared light across various frequency ranges, where absorbed wavelengths cause molecular motion.
📈 Results are presented as an absorption spectrum with intensity on the y-axis and wave number on the x-axis.
🔗 The location, shape, and height of peaks directly relate to the types of chemical bonds (functional groups) present in the material's backbone (e.g., in polycarbonate).
📑 The raw spectrum is compared to a database of known reference spectra, often requiring an experienced analyst to combine several library spectra for a perfect match in complex cases.

Primary Applications of FTIR Testing
✅ Material Identification and Quality Control: Used to confirm correct incoming materials, de-formulate substances to determine chemical makeup, or verify the correct resin was used during failure investigations.
🧼 Contamination Analysis: Identifying the chemical makeup of contaminants to quickly determine their source, which reduces downtime and improves component quality.
🌡️ Environmental Modification Analysis: Investigating how polymeric materials have been modified due to environmental conditions to determine the root cause of degradation during use.
🧪 Reaction Monitoring: Utilizing FTIR to monitor reaction rates and progress for thermosetting resins, adhesives, and potting agents during process setup or failure analysis.

Limitations of FTIR Testing
⚠️ Difficulty Differentiating Similar Structures: Materials with very similar backbones (e.g., two different polyamide materials like 6 and 6,6) may yield nearly indistinguishable spectra requiring additional tests.
📚 Reliance on Libraries: Precise identification is difficult if the specific compound or material grade (e.g., Lexan 121 vs. Lexan 141) is not present in the comparison library.
📉 Additive Detection Limits: Detection limits for most additives are generally between 1% and 5%, meaning these components might require additional test methods to identify.
🧮 Quantification Challenges: Quantification of components is difficult using FTIR alone and requires significant method development to achieve accurate results.

Key Points & Insights
➡️ FTIR provides a material "fingerprint" based on chemical bond absorption patterns, essential for identifying organic solids and liquids.
➡️ Material analysts often combine multiple library spectra through knowledge of polymer chemistry when a single perfect match is not found.
➡️ Key applications include quality control, contamination source identification, and monitoring polymer degradation.
➡️ Be aware that FTIR struggles to resolve materials with very similar chemical structures and has detection limits for additives usually around 1% to 5%.

📸 Video summarized with SummaryTube.com on Jan 12, 2026, 12:12 UTC