Evaluation of Visible and Near-Infrared Spectroscopy as a Tool for Assessing Fiber Fineness during Mechanical Preparation of Dew-Retted Flax

Abstract

Flax fiber must be mechanically prepared to improve fineness and homogeneity of the sliver before chemical processing and wet-spinning. The changes in fiber characteristics are monitored by an airflow method, which is labor intensive and requires 90 minutes to process one sample. This investigation was carried out to develop robust visible and near-infrared calibrations that can be used as a rapid tool for quality assessment of input fibers and changes in fineness at the doubling (blending), first, second, third, and fourth drawing frames, and at the roving stage. The partial least squares (PLS) and principal component regression (PCR) methods were employed to generate models from different segments of the spectra (400-1100, 1100-1700, 1100-2498, 1700-2498, and 400-2498 nm) and a calibration set consisting of 462 samples obtained from the six processing stages. The calibrations were successfully validated with an independent set of 97 samples, and standard errors of prediction of 2.32 and 2.62 dtex were achieved with the best PLS (400-2498 nm) and PCR (1100-2498 nm) models, respectively. An optimized PLS model of the visible-near-infrared (vis-NIR) spectra explained 97% of the variation (R(2) = 0.97) in the sample set with a standard error of calibration (SEC) of 2.45 dtex and a standard error of cross-validation (SECV) of 2.51 dtex R(2) = 0.96). The mean error of the reference airflow method was 1.56 dtex, which is more accurate than the NIR calibration. The improvement in fiber fineness of the validation set obtained from the six production lines was predicted with an error range of -6.47 to +7.19 dtex for input fibers, -1.44 to +5.77 dtex for blended fibers at the doubling, and -4.72 to +3.59 dtex at the drawing frame stages. This level of precision is adequate for wet-spinners to monitor fiber fineness of input fibers and during the preparation of fibers. The advantage of visNIR spectroscopy is the potential capability of the technique to assess fineness and other important quality characteristics of a fiber sample simultaneously in less than 30 minutes; the disadvantages are the expensive instrumentation and the expertise required for operating the instrument compared to the reference method. These factors need to be considered by the industry before installing an off-line NIR system for predicting quality parameters of input materials and changes in fiber characteristics during mechanical processing.

Characterization of radio frequency assisted water retting and flax fibers obtained

“…It is obvious that the Tex values of fibers are consistent with the results of degumming rate of RF assisted water retting presented above. Compared to the spinning flax fiber fineness of 4.02 tex in the work conducted by Sharma and Reinard (2004), the 6 d-90 • C and 10 d-90 • C treated fiber yielded reasonable fineness values.…”

Rapid techniques for assessing fibre quality of flax breeding lines and cultivars using visible and near infrared spectroscopy, and thermal analysis

“…Traditionally water‐retted fibres lose the residual colour of the retted stems, as a result of a combined action of wind, rain and sun, during wetting and drying of the stooks (bundle of retted stems) in open fields (Dujardin, 1948). The fineness of the samples ranged between 46.75–71.70 dtex (Table 4), which indicated that the experimentally water‐retted fibres were coarse compared with a fineness range of 35.34–56.5 dtex for scutched and hackled water‐retted fibres reported by Sharma & Reinard (2004).…”

“…The leverage, outlier detection, ratio of calibrated to validated explained variance, ratio of validated to calibrated explained variance and total explained variance limits during the calculation were set at 3.0%, 3.0%, 0.5% and 0.75%, and 20%, respectively. The spectra obtained from an extensive sample set of dew‐retted and water‐retted fibres taken from mechanical fibre preparation lines (Sharma & Reinard, 2004) were employed to develop NIR (1100–2500 nm) equation for predicting fibre fineness.…”

“…A research group based at the Queen’s University of Belfast has made significant contributions in a number of aspects relating to the production, microbiology of retting and quality assessment of flax fibre and yarn. Instrumental techniques, such as visible and near infrared spectroscopy (Vis–NIRS) and thermal analysis have been used, allowing the development of rapid techniques for assessment of fibre (Sharma & Kernaghan, 1988; Sharma et al , 1996, 1999; Sharma & Reinard, 2004), yarn (Sharma, 1996; Faughey & Sharma, 2001) and fabric quality parameters (McCall et al , 2001; Whiteside et al , 2001).…”

Testing of natural textile fibres

“…(2000) used diffuse refl ectance FT-IR and other techniques to study the surfaces of modifi ed sisal. Sharma and Reinard (2004) explored the potential of visible and near IR spectroscopy as a tool for the rapid quality assessment of fl ax fi bres during the spinning process. They successfully focused on assessment of the quality of input fi bre and changes in fi neness at all stages from the doubling (blending) through to the roving stage.…”