FTIR spectrometers employing attenuated total reflection (ATR) sampling interfaces are proven and powerful tools for the analysis of polymeric materials. The Agilent Cary 630 FTIR spectrometer offers unique features and class-leading performance, making quantitative analysis of polymers fast and easy. This application note focuses on the measurement of key components in two important copolymeric materials: the styrene content in styrene butadiene rubber (SBR) and the ratio of polyethylene to vinyl acetate in polyethylene vinyl acetate (PEVA) polymer. The Cary 630 FTIR, equipped with a single reflection Diamond ATR sampling accessory, is used for these measurements.
The document details how to use the Agilent Cary 630 FTIR spectrometer equipped with a single reflection Diamond ATR accessory to perform quantitative analysis on polymeric materials. It focuses on measuring styrene content in Styrene Butadiene Rubber (SBR) and determining the ratio of polyethylene to vinyl acetate in Polyethylene Vinyl Acetate (PEVA).
Two specific analytical methods are developed: a calibration for SBR based on polystyrene absorbance bands at 699 cm⁻¹, achieving a correlation coefficient of R²=0.999; and a method for PEVA using the peak area ratio of VA absorbance (1236 cm⁻¹) to PE absorbance (1467 cm⁻¹), also yielding R²=0.999. The note highlights the speed, accuracy, and ease of use provided by the MicroLab FTIR software.
| Correlation coefficient (SBR) | R²=0.999 |
|---|---|
| Limit of detection (PS in SBR) | 0.09% |
| Correlation coefficient (PEVA) | R²=0.999 |
| Limit of detection (VA in PEVA) | 0.03 wt% |
| Limit of quantitation (VA in PEVA) | 0.10 wt% |
The limit of detection is 0.09%, calculated as three times the standard deviation of the 0% replicate data.
The limit of quantitation (LOQ) is 0.10 wt% VA.
It is measured using a peak area ratio of the 1236 cm⁻¹ VA absorbance band to the PE absorbance at 1467 cm⁻¹.