FT-Mid-IR Spectroscopic Investigation of Fiber Maturity and Crystallinity At Single Boll Level and a Comparison with XRD Approach

In the previous study, we have reported the development of simple algorithms for determining fiber maturity and crystallinity from FT-IR measurement, on the basis of a large and diversified pool of cotton fibers. Due to the micro-sampling feature of the technique, we were able to study the fiber maturity and crystallinity at different portions of single boll. Meanwhile, we attempted to use the same fibers to calibrate the X-ray diffraction (XRD) measurement. This is because, despite considerable efforts in developing the curve-fitting protocol to evaluate the crystallinity index (CI) from XRD, in its present state XRD measurement can only provide a qualitative or semi-quantitative assessment of the amounts of crystalline and amorphous cellulosic components in a sample. The greatest barrier to establish quantitative XRD is the lack of appropriate cellulose standards needed to calibrate the measurements. In practice, samples with known CIs are very difficult to be prepared or determined. As an approach, we might assign the samples with reported CIs from FT-IR procedure. Hence, this study also reported the development of a simple XRD algorithm, over time-consuming and subjective curve-fitting process, for direct determination of cotton cellulose CI by correlating XRD with the use of FT-IR CI as references.