Journal Article

Effects of ball milling on the structure of cotton cellulose

Vincent Edwards, J., Potthast, Antje, Nam, Sunghyun, Rosenau, Thomas, Kang, Xue, Santiago Cintrón, Michael, Xu, Feng, Ling, Zhe, Wang, Tuo, Cheng, H. N., Kim, Seong H., Delhom, Christopher D., Makarem, Mohamadamin, Bacher, Markus, King, Holly, French, Alfred D.

2019

Overview

Cellulose is often described as a mixture of crystalline and amorphous material. A large part of the general understanding of the chemical, biochemical and physical properties of cellulosic materials is thought to depend on the consequences of the ratio of these components. For example, amorphous materials are said to be more reactive and have less tensile strength but comprehensive understanding and definitive analysis remain elusive. Ball milling has been used for decades to increase the ratio of amorphous material. The present work used 13 techniques to follow the changes in cotton fibers (nearly pure cellulose) after ball milling for 15, 45 and 120 min. X-ray diffraction results were analyzed with the Rietveld method; DNP (dynamic nuclear polarization) natural abundance 2D NMR studies in the next paper in this issue assisted with the interpretation of the 1D analyses in the present work. A conventional NMR model’s paracrystalline and inaccessible crystallite surfaces were not needed in the model used for the DNP studies. Sum frequency generation (SFG) spectroscopy also showed profound changes as the cellulose was decrystallized. Optical microscopy and field emission-scanning electron microscopy results showed the changes in particle size; molecular weight and carbonyl group analyses by gel permeation chromatography confirmed chemical changes. Specific surface areas and pore sizes increased. Fourier transform infrared (FTIR) and Raman spectroscopy also indicated progressive changes; some proposed indicators of crystallinity for FTIR were not in good agreement with our results. Thermogravimetric analysis results indicated progressive increase in initial moisture content and some loss in stability. Although understanding of structural changes as cellulose is amorphized by ball milling is increased by this work, continued effort is needed to improve agreement between the synchrotron and laboratory X-ray methods used herein and to provide physical interpretation of the SFG results.

• Publisher: Springer Netherlands,Springer Nature B.V,Springer
• Subject: Amorphization / Amorphous materials / Ball milling / biofuels (including algae and biomass), bio-inspired, membrane, carbon sequestration, materials and chemistry by design, synthesis (self-assembly) / Bioorganic Chemistry / Carbonyl groups / Carbonyls / Cellulose / Cellulose fibers / cellulosic materials / Ceramics / Chemistry / Chemistry and Materials Science / Composites / Cotton / Cotton fibers / crystal structure / Crystallites / Crystals / electron microscopy / Field emission / Fourier transform infrared spectroscopy / Fourier transforms / Gel chromatography / Glass / Infrared spectroscopy / light microscopy / lint cotton / Methods / milling / moieties / Moisture content / molecular weight / Natural Materials / NMR / Nuclear magnetic resonance / nuclear magnetic resonance spectroscopy / Optical microscopy / Organic Chemistry / Original Paper / particle size / Physical Chemistry / Physical properties / Polymer Sciences / Raman spectroscopy / Rietveld method / Software / Sustainable Development / Tensile strength / Thermogravimetric analysis / thermogravimetry / water content / X-radiation / X-ray diffraction / X-rays