Direct and Rapid Determination of Cotton Maturity by FT-Mid-IR Technique

Immature fibers, which have little cell wall thickening relative to fiber perimeter, were found to be prone to entanglement formation during mechanical processing and also to alter the desired color appearance in dyed yarn and fabric products. Microscopic and instrumental devices have been developed to measure cotton fiber maturity in direct and indirect ways. In general, microscope based direct method can distinguish mature fibers from immature ones, but the degree of maturity is difficult to assess because the procedure is subjective and depends on one’s judgment to assign the fibers into appropriate class. Indirect methods require a large number of samples (> 0.5 g), utilize air-flow measurements and a theoretical approach, and most notably, depend on direct methods’ maturity references to calibrate the systems for the accuracy and performance. As a different approach, we collected Fourier transform mid-infrared (FT-mid-IR) spectra of mature and immature cottons and discovered significant spectral differences between the two types of fibers. The characteristic IR bands were identified and further used to develop a simple three-band algorithm for determining fiber maturity.  The result was validated by independent measurements of image analysis, AFIS, and HVI micronaire. This procedure has the potential to be a rapid, routine, accurate, and nondestructive measuring technique, because it needs minimal sample preparation and is based on the structural differences between immature and mature fibers.