Shimadzu FTIR talk letter vol. 36

Significance of the Topic

Composite materials and plastics play a critical role across aerospace, industrial, and consumer applications. Enhancing structural performance, functionalizing polymer matrices, and accurately characterizing both virgin and degraded polymers are essential for innovation, safety, sustainability, and effective recycling.

Objectives and Overview

This summary integrates three studies and a system overview:

• Development of carbon fiber-reinforced plastics (CFRP) with intrinsically conductive polymer matrices to improve lightning strike resistance without metal layers.
• Fundamentals and advances of Fourier transform infrared (FTIR) interferometers, focusing on high-precision measurements.
• FTIR analytical procedures for identifying and characterizing plastics, including biomass and biodegradable resins, and assessing UV- or heat-degraded materials.
• Introduction to Plastic Analyzer, an FTIR-based system tailored for plastics analysis.

Methodology and Instrumentation

• Conductive polymer composites: Polyaniline (PANI) doped with dodecylbenzenesulfonic acid (DBSA) and cross-linked with divinylbenzene (DVB). FT-IR (Shimadzu IRAffinity-1S, ATR) monitored doping and curing.
• Interferometer design: Michelson interferometer using He-Ne laser for optical path control; dynamic alignment via piezo actuators maintains mirror parallelism (±0.5 arcsec) for accurate interferograms.
• Plastic analysis: Single-reflection ATR (QATR-S) and IR microscopy (AIM-9000) on IRSpirit™ and IRTracer™-100 spectrometers. UV- and thermal-damaged plastics libraries enable identification of aged or degraded polymers.

Main Results and Discussion

• CFRP with conductive PANI matrix showed negligible lightning damage versus severe damage in epoxy-only CFRP, suggesting metal mesh layers can be reduced or eliminated.
• Dynamic alignment interferometers produced high-quality interferograms with sampling interval stability to 0.1 % and robust noise reduction.
• ATR-FTIR successfully distinguished biomass-derived PE from conventional PE, identified starch-based biodegradable films, and separated PHBH versus PP straws. Degraded window shade surfaces matched UV-aged PP spectral patterns.

Benefits and Practical Applications

• Lightweight CFRP structures with intrinsic lightning protection reduce weight, cost, and galvanic corrosion risk.
• High-precision FTIR instruments support broad materials R&D, QA/QC, and forensic analysis of polymer degradation.
• Plastic Analyzer streamlines plastic identification, contaminant analysis, and aging assessment for industrial and environmental laboratories.

Future Trends and Opportunities

Continued development of multifunctional polymer composites (e.g., self-sensing, electromagnetic shielding) and integration of FTIR with AI-driven spectral libraries will enhance rapid, in-situ materials diagnostics. Advances in laser sources and miniaturized interferometers may enable portable field FTIR for on-site plastics sorting and environmental monitoring.

Conclusion

By combining advances in conductive polymer composites, precision FTIR interferometry, and tailored analytical workflows, Shimadzu’s technologies address critical challenges in materials performance and sustainability. Plastic Analyzer and dynamic alignment FTIR systems exemplify the integration of instrumentation and methodology for next-generation polymer analysis.

References

• V. Kumar, T. Yokozeki et al., “Mechanical and electrical properties of PANI‐based conductive thermosetting composites,” J. Reinforced Plastics Compos., 34:1298, 2015.
• T. Yokozeki et al., “Development and characterization of CFRP using a polyaniline‐based conductive thermoset matrix,” Compos. Sci. Technol., 117:277, 2015.
• Jiro Hiraishi (ed.), Fourier Transform Infrared Spectroscopy—FT‐IR for Chemists, Gakkai Shuppan Center.
• METI, “Fee‐Incurring Plastic Checkout Bags Starts on July 1, 2020,” 2020.