Determination of cotton linter to wood ratio in cellulose

Importance of the topic

Determining the proportion of cotton linter to wood pulp in cellulose is essential for controlling the viscosity of carboxymethyl cellulose (CMC), a widely used suspending agent in pharmaceutical and chemical industries.

Objectives and overview

This study aimed to develop a Vis-NIR spectroscopic model for rapid, non-destructive quantification of cotton linter and wood pulp ratios in cellulose samples, replacing laborious traditional methods.

Methodology and instrumentation

Samples covering 0–100% cotton linter content were measured in reflection mode over 400–2500 nm using a NIRS DS2500 Analyzer with a DS2500 Iris adapter. Spectral data were processed with Vision 4.03 software employing baseline correction at 850 nm and partial least squares (PLS) regression.

Main results and discussion

Visible range spectra (400–550 nm) showed a clear linear relationship with linter content. Combining visible and NIR regions (420–1080 nm, 1120–2480 nm) yielded a PLS model with three factors, achieving R2 = 0.9982, SEC = 1.6934, SEP = 1.5452, and F-value = 1276.35, indicating excellent predictive performance.

Benefits and practical applications

The Vis-NIR method significantly reduces analysis time, allows at-line or in-process monitoring, and supports quality control by predicting CMC viscosity based on linter-to-wood ratio.

Future trends and possibilities

Further integration of miniaturized NIR sensors, advanced chemometric algorithms, and process analytical technology (PAT) frameworks could enable real-time monitoring and automated feedback in pulp processing.

Conclusion

Vis-NIR spectroscopy offers a fast, accurate, and non-destructive approach for determining cotton linter to wood pulp ratios, enhancing efficiency and consistency in CMC production.