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United States Department of Agriculture

Agricultural Research Service

Research Project: New and Improved Assessments of Cotton Quality

Location: Cotton Structure and Quality Research

2012 Annual Report


1a.Objectives (from AD-416):
Objective 1: Develop new industrially supported methods to assess cotton quality. Sub-objective 1a: Develop ways to characterize short fibers in cotton. Sub-objective 1b: Develop methods to measure seed coat fragments. Sub-objective 1c: Develop assessment methods for cotton properties that may contribute to cotton textile processability and product quality, but not conventionally assessed, such as micronaire and its components (such as maturity), three-dimensional color, and environmental impact on fiber properties. Objective 2: Develop new industrially supported methods to establish scientific foundations for standards and the next generation instruments for cotton classing. Sub-objective 2a: Develop new algorithms and methods to obtain fiber length distributions from a rapid fiber beard testing method. Sub-objective 2b: Characterize the distributions of key cotton properties as well as single cotton fiber measurement. Objective 3: Develop new industrially supported assessment techniques and methods for cotton producers, breeders, and others to evaluate fiber properties at various fiber development or processing stages based on small samples. Sub-objective 3a: Develop assessment techniques and methods to evaluate fiber properties at various fiber development stages based through sampling/measurement of the cotton product at-line and/or in the cotton field. Sub-objective 3b: Develop assessment techniques and methods to evaluate fiber properties and textile products during processing stages of small samples of fiber into textile goods.


1b.Approach (from AD-416):
This research is a comprehensive effort to develop improved or new testing methods that are not currently in the cotton classing system so that the textile manufacturers can more efficiently select and utilize cotton to reduce cost and improve product quality and so that our international customers can get quantified U.S. cotton quality. The value of adding new measurements will be studied by processing large numbers of cotton samples into textile yarns and fabrics. The first objective develops new methods to assess cotton quality. Statistical modeling will be used to characterize short fibers in cotton. An automated image analysis system will be developed to relate seed coat fragments to textile processability and product quality. Microscopy and molecular spectroscopy will be used to develop measurement methods and to characterize fiber micronaire and its components (maturity, fineness). Advanced color and spectroscopic instrumentation, combined with statistical modeling, will be used to measure color and trash components. A room whose environment (moisture level) can be changed and controlled will be used to determine the impacts of moisture on quality assessments and instrumentation. The second objective develops methods for fiber length distributions and single fiber measurements. New beard methods and statistical modeling will be used to obtain fiber length distributions. Automated constant-rate of transverse tensile testers and statistical modeling will be used to monitor key single fiber properties (strength, fineness, etc.) and to establish relationships between single fiber properties and conventional bulk properties. The third objective develops new quality assessment tools for cotton breeders and others to evaluate fiber properties at various fiber development or processing stages based on small samples. New molecular spectroscopy, imaging, and textile instrumentation will be used to assess fiber properties and quality at-line or in the field. Very small scale processing systems (50-100 grams) will be developed and used to assess fiber properties and processability from carding to knitting or weaving on miniature equipment.


3.Progress Report:
ARS scientists at Southern Regional Research Center in New Orleans,LA completed a comprehensive study on optimal selection of fiber length parameters to predict yarn properties. Various cotton length parameters were obtained from a selection of cottons covering a wider range of properties. Optimal statistical models were developed to predict ring and open-end spun yarns’ properties and processability. ARS scientists continued instrumental measurements of Seed Coat Fragments (SCF). Dark specks in fabrics were measured with the Autorate image analysis system and compared to fiber properties measured on the Advanced Fiber Information System (AFIS). Statistical analysis on the test results of fiber properties, yarn defects and fabric dark specks revealed that seed coat neps and neps/gram were the most important AFIS variables for predicting the dark specks (and SCF) in fabrics.

A method was developed using Near Infrared (NIR) instruments (bench-top and portable) to measure fiber micronaire, maturity, and fineness in the laboratory. Instrumental, sampling, and operational procedures were established. The NIR simultaneous measurement of cotton fiber micronaire, maturity, and fineness was rapid and easy to perform. In addition, methods in Fourier-Transform Infrared (FT-IR) spectroscopy were used to analyze binary cotton trash mixtures. Using the developed spectral libraries, over 90% of the total binary cotton trash mixtures were correctly identified.

A method was developed to compute the fiber staple curve and length distribution from optical signals acquired by measuring a tapered fiber bundle. Different fiber length parameters were calculated from the staple diagrams. Results showed good agreements with AFIS results, which were used as the reference.

A large set of cottons from domestic and international sources has been gathered. These cottons were tested using standard bulk property test methods. A subset of these cottons was characterized using single fiber measurement technologies. All of the relevant data plus descriptive information on the origin of the material has been cataloged and stored as part of a comprehensive database. Signal analysis methods to obtain distributions of properties is underway, as is the adoption of two new fiber test instruments which report both bulk properties and their distributions.

To address stakeholders’ need for measure cotton fiber color in remote locations (e.g., warehouse), ARS scientists expanded the research of measurements with portable color spectrophotometers. The diffuse reflectance color value Rd was added. Three color spectrophotometers were evaluated and very good inter-instrument agreement was observed for each unit, with over 88% of the samples meeting agreement criteria.

Samples were processed in commercial textile mills, the miniature-scale and large-scale systems for comparison of processing and performance. A complete overhaul of the large-scale processing line is being carried out to better reflect current industry practices and capabilities. Breeder samples were processed on the small-scale equipment to evaluate fiber properties and assess the technique as a tool for breeders.


4.Accomplishments
1. Cooperation/support from stakeholders. ARS scientists at Cotton Structure Quality (CQS)at Southern Regional Research Center (SRRC) in New Orleans, LA worked with Cotton Incorporated on cotton short fiber content measurements; color distributions by image analysis; color at-line/portable color measurements; Cottonscope® maturity and fineness measurements for researchers, mills, and breeders; near infrared fiber measurements for breeders; and fiber moisture measurements. An agreement on length distributions was completed on 12/31/2011. Cotton Incorporated was enabled by the Cotton Research and Promotion Act of 1966 and is the research and promotion arm of the cotton industry. The funding of the agreements demonstrates that the scientists of CSQ are working closely with stockholders to address high impact issues of the cotton industry. Procedures and protocols and end-state agreement criteria for inter-instrument agreement between purchased color spectrophotometers (MSEZ) were established.

2. Remote location cotton color measurements. Concerns were expressed that some cotton bales, especially those transported overseas, appear to have changed significantly in yellowness from their initial Uster® High Volume Instrument (HVI) color measurements. It was previously demonstrated in the laboratory that portable color spectrophotometers could be used to measure cotton fiber yellowness. The portable instrument measurements were rapid, precise, and accurate, and the results can be transferred to external device for remote field operations. The technology was transferred to Cotton Incorporated, and the new color measurement technology implemented into their Engineering Fiber Selection System’s (EFS®) MILLNet™ software for mill bale selection. Preliminary field trials were performed on over 400 bale cotton lint samples at a foreign textile mill that purchases and uses U.S. cotton. The mill reported that the interface and hardware was fast and easy to operate. Very good color agreement was observed between the mill’s HVI unit and the ARS-MILLNet™ system, with distinct and significant yellowness color shifts detected. Based on these results, Cotton Incorporated has purchased two additional portable color units for EFS color measurements in the laboratory, mill, and warehouse. ARS will set-up and validate the units for Cotton Incorporated, using the new ARS protocols.

3. Cottonscope measurements of lint cotton fiber maturity and fineness. Common direct measurements of fiber maturity and fineness involve the use of slow, laborious cross-sectional image analysis and microscopy, chemicals, or expensive fiber testing instruments. Interest had been expressed in a rapid, precise, and accurate direct measurement of cotton fiber maturity and fineness. A new commercial instrument—the Cottonscope®--measures fiber maturity and fineness (using polarized light microscopy and image analysis in a water-based system). A program was implemented to assess the potential and capabilities of the Cottonscope®. Measurement and method feasibility for the rapid, precise, accurate, and simultaneous measurement of cotton fiber maturity and fineness using the Cottonscope® was demonstrated. The measurement was straight-forward, fast, and easy to perform. Method agreements between the Cottonscope® and the reference image analysis maturity and fineness results were very good, with low residuals and few outliers. The Cottonscope® correlation to micronaire was superior to that of the reference method. All end-state criteria were met or exceeded. Recommended operational protocols and standard procedures were developed. Cotton Structure Quality Research Unit (CSQ) at SRRC in New Orleans, LA is a founding member of and a major collaborator in the Cottonscope® User Group—research organizations examining hardware, software, and instrument/measurement procedures and improvements. CSQ is the lead for fiber calibration standards development.

4. Image analysis measurements of seed coat fragments. Dark specks in yarns and fabrics are often the result of Seed Coat Fragments (SCFs), which are parts of the seed surface that have broken from the seed during mechanical processing such as ginning. SCFs are quality concern for downstream processing. The Autorate image analysis system has been developed and optimized for measuring the dark specks in fabrics due to SCFs, resulting in accurate and fast measurements of SCFs in undyed fabrics. Measurement protocols and sampling parameters were developed. By correlating the Autorate results with typical fiber measurements, key fiber properties influencing SCF measurements can be determined, which can be used by breeders in variety selections. In addition, it can be used for textile mills to take corrective measures to avoid costly fabric defects.

5. Over 600 breeder samples have been processed on the miniature-scale processing system. Any new cotton variety or new ginning technology should be assessed by textile processing. However, a full-scale textile processing requires a lot of raw materials, uses more energy, and is time consuming. A miniature-scale textile processing system has been established at the Cotton Structure and Quality Research Unit at ARS SRRC in New Orleans, LA. Samples were processed on miniature-scale equipment to show the success at replicating commercial results. Samples have been processed for comparison to large-scale processing and in-support of cotton breeders and researchers. Small-scale fabric formation has been optimized and used in direct support of public researchers and the domestic textile industry. Collaborations have been put in place with commercial partners to further develop this work.

6. Presence of trash (or non-lint materials). The presence of trash or non-lint materials in commercial cotton bales at varying amounts degrades the market values, requires additional cleaning process, and impacts the end-use qualities for yarn and fabric products. In order to ensure a fair trading, the USDA’s Agricultural Marketing Service (AMS) has implemented the high volume instrument (HVI) readings as a universal quality index to grade the cottons. Comparing to HVI’s geometric method that represents the trash portion only on a sample’s surface, traditional Shirley Analyzer (SA) is a gravimetric-based method and is being routinely utilized in the laboratories. With the increasing acceptance of HVI readings in domestic and international trading, there is a continued interest in understanding the conversion constant between two trash testing results from the customers, regulatory and trading organizations. Due to the complexity of trash type and size and also the nature of HVI and SA tests, apparently relating two types of trash results is a great challenge. ARS researchers at New Orleans, LA, addressed the need by proposing an innovative approach to group the samples and then verifying the findings from independent Near Infrared (NIR) measurement. This research will have a direct impact on domestic and foreign customers and regulatory agencies, and also trading organizations. The outcome helps cotton engineers, researchers, ginners, and trading regulators in understanding the HVI trash test.

7. Identification of components of cotton trash mixtures. Cotton is machine harvested and comingled with various non-fibrous trashes such leaf, bark, and seed coat fragments. These trash components can not be completely removed during ginning and cause different problems in downstream textile processing. The current traditional fiber test methods and instruments can’t identify these different components. ARS scientists at Southern Regional Research Center in New Orleans, LA developed technology to identify trash components from binary trash mixtures using Near Infrared (NIR) and Attenuated Total Reflectance (ATR)/Fourier-Transform infrared (FT-IR) spectroscopy as well as Thermo-Gravimetric Analysis (TGA). The expansion and updating of these spectral libraries will make these techniques even more robust through the potential for development of equipment for trash-specific removal and sorting from cotton lint. The use of NIR and ATR/FT-IR spectroscopy along with TGA to identify binary trash mixtures is advantageous to the textile community and cotton breeders.

8. New method for obtaining cotton fiber length distributions by using staple diagram and optical signal of a tapered fiber bundle (beard). As a natural product, cotton fiber length has a distribution even when they are from a single cottonseed. Although the distribution of cotton fibers length provides complete information on the cotton’s quality, the widely used rapid method by testing fiber beard can’t provide fiber length distribution. A new method and algorithm have been developed by ARS scientists at Southern Regional Research Center in New Orleans, LA to obtain the entire fiber length distribution by analysis the optical signals of testing a fiber beard and applying a staple diagram model, a type of data analysis. Different fiber length parameters were calculated from the staple diagrams. Results showed good agreements with Advanced Fiber Information System generated results, which were used as the reference. The staple diagram method shows a good potential in industrial implementation.

9. Cotton crystallinity determination. Concentration of cellulose component in developing cotton fibers produces changes in their compositions and structures (e.g., crystallinity). Although X-Ray Diffraction (XRD) method has been traditionally used to determine the fiber crystallinity, in its present state XRD procedure can only provide a qualitative or semi-quantitative assessment of the amounts of crystalline portion in a sample. The greatest barrier to establish quantitative XRD is the lack of appropriate cellulose standards needed to calibrate the XRD measurements. ARS researchers at New Orleans, LA, developed a method called three-band ratio algorithms based on a Fourier Transform Infrared (FT-IR) spectroscopy procedure to determine the fiber crystallinity in a direct way, as the method requires minimal sample preparation, permits routine analysis at both laboratory and on-field environments, and is easy to operate. This technology can reveal useful information on cotton crystallinity to cotton breeders and producers for cotton enhancement and to textile processors for fiber grading and quality control.

10. Cotton developmental characterization. Cotton fibers are natural plant products and their end-use qualities depend on their stages of growth. In general, the quantity of cellulose increases rapidly in developing cotton fibers, and this leads to a number of significant differences in compositions and structures between mature and immature (underdeveloped) fibers. Given the obvious distinctions between two types of fibers, a number of physical and chemical techniques have been proved to be effective in describing the fiber growth. Fourier-Transform Infrared (FT-IR) spectroscopy could be an alternative essential tool, as it permits routine analysis and is sensitive to delicate structure on cellulose. Despite the efforts of extracting useful information from relatively sharp infrared bands of cotton celluloses, their spectral features have not been well understood, mainly due to slight spectral differences between fiber celluloses and noncellulosic polysaccharides and also between the amorphous and crystalline celluloses. ARS researchers at New Orleans, LA, examined the IR spectral differences between immature and mature fibers by applying the generalized two-dimensional (2D) correlation spectroscopy. The results clearly showed the intensity increase or decrease of the bands ascribed to different carbon - oxygen confirmations of primary alcohols in crystalline regions, which are indicative of cotton fiber development and could be used to develop the sensing device for assessing the degree of fiber development. Cotton breeders and producers and also textile processors can benefit from this result for fiber grading and quality control.


Review Publications
Rodgers III, J.E., Elkholy, K.N., Cui, X., Delhom, C.D., Fortier, C.A. 2012. Fiber sample presentation system for spectrophotometer cotton fiber color measurements. Journal of Cotton Science. 16(2):117-124.

Fortier, C.A., Rodgers III, J.E., Foulk, J.A., Whitelock, D.P. 2012. Near-infrared classification of cotton lint, botanical and field trash. Journal of Cotton Science. 16:72-79.

Fortier, C.A., Rodgers III, J.E., Foulk, J.A. 2011. Investigation of the impact of instrumental and software applications on cotton and botanical trash identification by ultraviolet-visible spectroscopy. Journal of Cotton Science. 15:170-178.

Vogt, F., Luttrell, R.D., Rodgers III, J.E. 2011. New approaches for field analyses of cotton quality by means of near infrared spectroscopy supported by chemometrics. Analytical Letters. 44(15):2466-2477.

Rodgers III, J.E., Delhom, C.D., Fortier, C.A., Thibodeaux, D.P. 2012. Rapid measurement of cotton fiber maturity and fineness by image analysis microscopy using the Cottonscope®. Textile Research Journal. 82(3):259-271.

Bel, P., Xu, B. 2011. Measurements of seed coat fragments in cotton fibers and fabrics. Textile Research Journal. 81(19):1983-1994.

Liu, Y., Gamble, G.R., Thibodeaux, D.P. 2011. Potential of near infrared spectroscopy in the prediction of cotton fiber strength indices. Applied Engineering in Agriculture. 27(5): 839-843.

Liu, Y. 2012. Principal component analysis in the development of optical and imaging spectroscopic inspections for agricultural / food safety and quality. In:Sanguansat, P. Principle Component Analysis. Rijeka, Croatia: InTech. p. 125-144.

Liu, Y., Thibodeaux, D.P., Gamble, G.R. 2012. Characterization of attenuated total reflection infrared spectral intensity variations of immature and mature cotton fibers by two-dimensional correlation analysis. Applied Spectroscopy. 66(2):198-207.

Fortier, C.A. 2012. Fourier transform spectroscopy of cotton and cotton trash. Fourier Transform. In: Salih, S.M.,editor. Fourier Transform - Materials Analysis. InTech, 5 p.103-120.

Bel, P., Xu, B., Yao, X. 2011. White speck potential for mechanically harvested cottons. American Association of Textile Chemists and Colorists Review. 11(4):59-65.

Last Modified: 4/20/2014
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