ANALYTICAL TECHNIQUES FOR DIFFERENTIATING HUACAYA AND SURI ALPACA FIBERS DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Sohie Shim, M.S. ***** The Ohio State University 2003 Dissertation Committee: Approved by Professor Kathryn A. Jakes, Adviser Professor Terry L. Gustafson Professor Matthew S. Platz Adviser Textiles and Clothing Graduate Program Professor Susan L. Zavotka ABSTRACT The alpaca industry is burgeoning in North America. The two breeds of alpacas, i.e. huacaya and suri, are very different in appearance despite the close genetic relationship. The most apparent difference is in the crimp characteristics of the fibers in these animals. Because ortho- and para-cortical cell structure is believed to be associated with crimp in sheep’s wool, differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) were used for the investigation of the cortical cell structure of alpaca fibers. Energy dispersive spectrometry (EDS) and IR spectroscopy were also conducted to elucidate the sulfur distribution, cystine oxidation content and α-helical content related to the cortical cell compositions. DSC results determined that huacaya have an ortho and para bicortical structure whereas suri fibers mostly consist of paracortical cells. Similar results were observed in SEM imaging experiments with plasma etched fiber cross-sections. SEM images illustrate that huacaya fibers have smaller cortical cells assigned to the orthocortex, and larger cortical cells to the paracortex. Localization of cortical cells was observed in huacaya fibers. However, suri fibers only show randomly mixed cells that are likely to be paracortex. The composition of bicomponent cortical cells obtained using DSC or the cortical cell size distribution observed by SEM can be used for discrimination of huacaya and suri fibers. Sulfur analysis performed by EDS was unable to discriminate huacaya ii and suri fibers readily. The use of Igor Pro software enhanced the presentation of sulfur distribution by means of a three dimensional rotation. IR spectra of huacaya and suri fibers distinguish neither cystine oxidation content nor helical structures. iii Dedicated to my beloved husband Whatever I called you by while I was writing this you are not it, honey. iv ACKNOWLEDGEMENTS I wish to thank my adviser, Professor Kathryn A. Jakes for her constant support, encouragement and intellectual nourishment. I would like to give special thanks to Professor Terry Gustafson, Professor Matthew Platz, and Professor Susan Zavotka for the commitment to this dissertation. I also would like to thank Dr. John Mitchell and Dr. Sreenivas Bhattiprolu for technical advice and guidance. I acknowledge Magical Farms, Inc., Litchfield, Ohio and Alpaca Jack's Suri Farm, Findlay, Ohio who generously donated alpaca fibers for the research. Partial support for this research was provided with funds from the Lois Dickey- Ester Meacham Endowment, and by the Cynthia Ann Spafford Fellowship. v VITA January 19, 1973 ..........................Born – Taejon, Korea 1995..............................................B.S. Clothing and Textiles, Seoul National University 1997..............................................M.S. Clothing and Textiles, Seoul National University 1998 – Present..............................Graduate Teaching and Research Associate, The Ohio State University PUBLICATIONS Shim, S. & Park. C. (1997). Interface properties and detergency of the mixed surfactant solution. Journal of Korean Society of Clothing & Textiles, 21(3), pp 623-640. FIELDS OF STUDY Major Field: Textiles and Clothing Minor Field: Chemistry vi TABLE OF CONTENTS Abstract...............................................................................................................................ii Dedication.......................................................................................................................... iv Acknowledgements............................................................................................................. v Vita..................................................................................................................................... vi List of Tables ..................................................................................................................... ix List of Figures..................................................................................................................... x 1. Introduction................................................................................................................... 1 1.1. History of the South American Camelid and the Current Economics of Alpaca Fiber................................................................................1 1.2. Hair Fibers.........................................................................................................4 1.2.1. The chemistry of wool fiber.................................................................. 5 1.2.2. The morphology of wool fiber.............................................................. 6 1.2.3. Alpaca fiber fleece types....................................................................... 8 1.2.4. Fiber evaluation.................................................................................... 8 1.3. Research Problem Statement .............................................................................9 1.3.1. Research.............................................................................................. 10 2. Differentiating Alpaca Fibers by Thermal Analysis.................................................... 16 2.1. Introduction......................................................................................................16 2.2. Thermal Analysis of Wool...............................................................................17 2.3. Method .............................................................................................................19 2.3.1. Materials ............................................................................................. 19 2.3.2. Experimental....................................................................................... 19 2.4. Results..............................................................................................................20 2.5. Discussion........................................................................................................22 2.6. Conclusion .......................................................................................................24 3. Differentiating Alpaca Fibers by Scanning Electron Microscopy and Energy Dispersive Spectrometry ................................................................................ 37 vii 3.1. Introduction......................................................................................................37 3.2. Method .............................................................................................................42 3.3. Results..............................................................................................................43 3.4. Discussion........................................................................................................46 3.5. Conclusions......................................................................................................49 4. Infrared Spectroscopy of Alpaca Fibers ...................................................................... 78 4.1. Introduction......................................................................................................78 4.2. Experimental....................................................................................................82 4.3. Results..............................................................................................................83 4.4. Discussion........................................................................................................85 4.5. Conclusions......................................................................................................87 5. Conclusions.................................................................................................................. 97 Bibliography ................................................................................................................... 102 viii LIST OF TABLES 1.1. Alpaca fleece prices according to AAC as of December 2000.................................. 12 1.2. Common amino acids in wool fiber........................................................................... 12 1.3. Classification for alpaca fibers................................................................................... 13 2.1. DSC peak temperatures of alpaca fibers derived by using TA instruments Universal Analysis software .................................................................. 26 2.2. DSC peak temperatures of alpaca fibers derived by using Grams/AI software...................................................................................................................... 27 2.3. DSC peak temperatures of suri alpaca fibers with two peak assumption derived by using Grams/AI software...................................................... 28 2.4. Ortho- and para-cortical cell compositions based on the enthalpy reported by Wortmann and Deutz (1998).................................................................. 29 4.1. Some IR absorbance frequencies of