Spectral Testing
Materials analysis uses light in the upper infrared range to identify polymer types and measure chemical compositions. Automated sorting equipment uses short-wave infrared spectroscopy to scan incoming textile waste for synthetic polymer contaminants before recycling. This non-destructive test measures the light reflected in the twelve hundred to twenty five hundred nanometer band to create a unique molecular signature of each material.
This spectral analysis makes it possible to sort mixed garments by their fiber content.
Contaminant Sorting
Plastic fragments like polypropylene bale twine can ruin large batches of cotton yarn if not removed early in the blowroom. Integrating short-wave infrared spectroscopy into the automated fiber sorting machines allows the system to detect these synthetic pieces as they pass through the feed chutes. This real-time detection triggers high-speed air valves that blow the contaminants out of the fiber stream.
Recycling Verification
Synthetic and natural fibers must be separated before chemical recycling can take place. Processors use short-wave infrared spectroscopy to sort mixed garments by their material composition, such as separating pure polyester from polyester-cotton blends. This accurate sorting ensures that the recycling reactors receive a uniform feedstock, which improves the quality of the recycled fiber.
Sensor Calibration
Moisture on the fiber surface can alter the infrared reflection spectrum and cause false readings. Technicians must calibrate the short-wave infrared spectroscopy system to account for fiber moisture content and ambient light.
