Determination of Irganox 1010 in polyethylene by infrared spectroscopy

Significance of the topic

Effective determination of antioxidant additives in polyethylene is crucial for ensuring material performance and durability in industrial applications. Irganox 1010 is a widely used stabilizer that prevents oxidative degradation during processing and service. A rapid, reliable analytical method supports quality control, reduces waste, and maintains consistent polymer properties.

Objectives and Overview of the Study

This work presents an infrared spectroscopic method for quantifying Irganox 1010 in polyethylene when the complete additive package is known. The approach focuses on a characteristic ester carbonyl absorption band of the antioxidant and uses a polymer reference band to correct for film thickness. The study aims to establish a simple, reproducible protocol suitable for process control rather than complex filled or pigmented resins.

Methodology and Instrumentation

Sample preparation relies on molding an analytically representative resin into uniform films of 0.5 to 0.7 mm thickness using a heated hydraulic press at 200 °C under nitrogen. The polymer films are then analyzed by Fourier transform infrared spectroscopy at 4 cm-1 resolution. Key instruments and accessories include

• An Agilent Cary 630 FTIR spectrometer with DialPath or TumblIR transmission cell (1000 micrometer path length)
• An alternative portable Agilent 5500 or 4500 Series FTIR
• Film micrometer for thickness measurements
• Hydraulic press with heated platens and chase mold

Calibration standards are prepared by blending known amounts of Irganox 1010 with polyethylene powder under nitrogen and molding films for analysis. A linear least squares regression correlates the ratio of additive absorbance at 1745 cm-1 to reference absorbance at 2019 cm-1 against known concentrations.

Main Results and Discussion

The method yields a highly linear calibration curve over the typical concentration range. Triplicate measurements of each standard and unknown film provide reproducible results. Using the MicroLab PC FTIR software, peak areas are integrated relative to baseline limits and a custom peak ratio component automatically calculates the weight percent of Irganox 1010. The real time sample viewing capability of the DialPath and TumblIR cells facilitates accurate repositioning and rapid replicate analysis.

Benefits and Practical Applications of the Method

The described procedure enables fast, accurate determination of antioxidant content in polymer films with minimal sample preparation effort. The flat cell mounting eliminates mounting errors and enhances reproducibility. This method is well suited for routine process control in polymer manufacturing and quality assurance laboratories.

Future Trends and Applications

Emerging possibilities include adaptation of this infrared method to other polymer additives, integration into inline or at line process analytical technology platforms, and coupling with chemometric models for multicomponent additive packages. Portable spectrometers and automated sample handling will further streamline field or production floor analysis.

Conclusion

The FTIR based measurement of Irganox 1010 in polyethylene films offers a straightforward, robust solution for additive quantification. Unique transmission cells and dedicated software simplify analysis while maintaining high accuracy and reproducibility.

References

Collins W, Seelenbinder J, Higgins F. Determination of Irganox 1010 in polyethylene by infrared spectroscopy. Agilent Technologies publication 5991-0457EN, 2012.