Impact of temperature and relative humidity on the near infrared spectroscopy measurements of cotton fiber micronaire

Authors: ZUMBA, JIMMY - Oak Ridge Institute For Science And Education (ORISE); Rodgers Iii, James; INDEST, MATTHEW - Oak Ridge Institute For Science And Education (ORISE)

Submitted to: Textile Research Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/18/2017
Publication Date: 7/31/2017
Citation: Zumba, J., Rodgers III, J.E., Indest, M. 2017. Impact of temperature and relative humidity on the near infrared spectroscopy measurements of cotton fiber micronaire. Textile Research Journal. https://doi.org/10.1177/0040517517720499.
DOI: https://doi.org/10.1177/0040517517720499

Interpretive Summary: A key cotton fiber property is micronaire, the indirect indicator of the fiber’s maturity (cell wall development or thickening) and fineness (linear density or size). Micronaire can impact the fiber’s quality, textile processing efficiency, and fabric dye consistency. As a key quality property, fiber micronaire is normally measured in a laboratory under tight standard temperature and relative humidity (RH) environmental conditions. Near infrared (NIR) spectroscopy measurements for fiber micronaire have previously been performed outside of the laboratory, but these measurements have at times been impacted by the lack of tight control of/non-standard environmental conditions. A program was implemented to determine the impact on NIR micronaire results for cottons conditioned under non-standard environmental conditions (low to high temperature and RH combinations), using both benchtop and portable NIR instruments. It was shown that the non-standard environmental conditions resulted in lower moisture at low temperature/RH and higher moisture at high temperature/RH. The degree of impact was not the same for different cottons. The NIR micronaire results were impacted by the non-standard conditioning for all instruments, with the lower wavelength portable instrument impacted the most. The impacts and deviations were greater at high temperature/RH compared to low temperature/RH conditioning. These results provide a rationale for the deviations observed previously for outside the laboratory micronaire measurements with portable NIR units.

Technical Abstract: A key cotton fiber property is micronaire, the indirect indicator of the fiber’s maturity (cell wall development or thickening) and fineness (linear density or size). Micronaire can impact the fiber’s quality, textile processing efficiency, and fabric dye consistency. As a key quality property, fiber micronaire is normally measured in a laboratory under tight standard temperature and relative humidity (RH) environmental conditions (21±1°C, 65±2% RH). Previous evaluations have demonstrated that near infrared (NIR) spectroscopy can be utilized to measure micronaire in the laboratory. NIR measurements have also been performed outside of the laboratory, but these measurements have at times been impacted by the lack of tight control of/non-standard environmental conditions. A program was implemented to determine the impact on NIR micronaire results for cottons conditioned under non-standard environmental conditions (low to high temperature and RH combinations), using both benchtop and portable NIR instruments. It was shown that the non-standard environmental conditions resulted in varying fiber moisture (lower moisture at low temperature/RH, higher moisture at high temperature/RH), which impacted the NIR spectral response. The degree of impact was not the same for different cottons. The NIR micronaire results were impacted by the non-standard conditioning for all instruments, with the lower wavelength portable instrument impacted the most. The impacts and deviations were greater at high temperature/RH compared to low temperature/RH conditioning. These results provide a rationale for the deviations observed previously in NIR micronaire results for outside the laboratory micronaire measurements with portable NIR units.