FTIR Plastic Analysis System

Significance of the Topic

The accurate identification of plastic materials, including those altered by heat or UV exposure, is critical for quality control, failure analysis and environmental monitoring. Traditional FTIR libraries often fail to recognize deteriorated plastics, leading to misclassification. Integrating specialized deterioration libraries enhances confidence in identifying aged or thermally stressed samples.

Study Objectives and Overview

This white paper presents the Plastic Analyzer system, a package built around an FTIR spectrophotometer and two proprietary libraries targeting UV- and thermally damaged plastics. The study demonstrates how the system distinguishes between standard, contaminated and degraded polymer samples to support contaminant analysis and microplastics research.

Instrumentation

• Fourier Transform Infrared Spectrophotometer (IRSpirit™)
• Single-reflection ATR attachment (QATR™-S)
• Plastic Analyzer method package
• UV-Damaged Plastics Library (300+ spectra from 14 polymer types)
• Thermal-Damaged Plastics Library (100+ spectra from 13 polymers)
• IR Pilot™ macro program and parameter files

Methodology

Unknown plastic samples are measured via single-bounce ATR-FTIR and spectra are automatically compared against both standard and deterioration libraries using optimized search parameters. The UV library contains time-resolved spectra from accelerated weathering, while the thermal library covers heating temperatures from 200 to 400 °C. Analysts receive ranked candidate matches reflecting both polymer type and degradation conditions.

Key Results and Discussion

Contaminant Analysis
The system identified a light brown semi-transparent contaminant on plated items. Standard library searches suggested polyethylene, but the Plastic Analyzer correctly ranked polyethylene heated at 250 °C (2 h) as the top match, providing insight into thermal history.

Deteriorated Polypropylene Analysis
PP samples exposed to UV for up to 550 h exhibited changes in carbonyl and hydroxyl absorption bands. Unlike generic libraries that misidentified polybutene, the UV-damaged library placed UV-irradiated PP as the top candidate, accurately reflecting exposure duration.

Benefits and Practical Applications

• Enhanced accuracy in identifying aged or contaminated plastics
• Facilitates fault and failure analysis by revealing thermal or UV exposure history
• Supports environmental and microplastics research through reliable spectral matching
• Streamlines QA/QC workflows with automated library searches

Future Trends and Opportunities

• Expansion of deterioration libraries to additional polymers and composite materials
• Development of quantitative metrics for degradation level assessment
• Integration of chemometric and machine learning tools for automated interpretation
• Coupling with microscopy and imaging for sub-millimeter plastic analysis
• Real-time monitoring of plastic aging in industrial or environmental settings

Conclusion

The Plastic Analyzer system leverages specialized UV and thermal degradation libraries together with FTIR-ATR measurements to reliably identify both pristine and deteriorated plastics. This approach addresses limitations of standard spectral libraries and supports a wide range of analytical applications from contaminant identification to microplastics research.

References

No external literature references were cited in the source document.