Benchmarking Cellulose Nanocrystals: From the Laboratory to Industrial Production Michael S. Reid 1, Marco Villalobos 2 and Emily D. Cranston 1* 1 Department of Chemical Engineering, McMaster University Hamilton, Ontario, Canada, LS 4L 2 Cabot Corporation, Billerica, MA, US, 121 *Corresponding author: ecranst@mcmaster.ca 1
Crystallinity X-ray Diffraction. XRD measurements, to obtain the degree of crystallinity, were performed on freeze dried CNCs samples using a Bruker D DAVINCI diffractometer (Bruker USA) with a cobalt sealed tube source (λ avg = 1.7926 Å), 35 kv, 45 ma with a parallel focus Goebel Mirror, Vantec 5 area detector, and.5 mm micro-slit and.5 mm short collimator over a 2θ range of -45. Si wafer blanks were subtracted from all sample measurements. Two dimensional area detector frames were integrated to produce diffraction patterns, which then underwent Rietveld refinement. Percent crystallinity was determined by deconvolution using the cellulose I single crystal information file (CIF) to define peak position and a fixed amorphous peak at 24.1. A pseudo-voigt function with linear background was used to fit peak shape and the CIF file with a March Dollase preferred orientation function model was used to fit peak intensity. For samples that contained both cellulose I and cellulose II structures the percentage of each crystal phase is presented. It is important to note that there are a number of methods described in the literature used to determine the crystallinity of cellulose and is not only limited to XRD.[1] [4] Furthermore, the validity and limitations of these methods and data fitting routines is a hotly debated topic and is beyond the scope of this work. Largely XRD is reported and the Rietveld refinement commonly considered to be the most accurate method.[5] [7] In a recent publication however, Ahvenainen et al. found good correlation with the five most common XRD fitting methods and the two dimensional Rietveld method.[] Moreover, within their work it is emphasized that comparison between samples and laboratories is extremely challenging. As such the crystallinity values presented here should be taken as relative (and comparable within this study) not absolute. Using the deconvolution method presented above the error in these measurements is taken to be 3-5%. 2
a)' 3, 2,5 1,5 5 b)' 1,4 1,2 6 4 2 1 12 14 16 1 2 22 Green-R-Si.raw_1 24 26 1alpha cellulose 1. % 3 32 34 36 3 4 1alpha cellulose 1. % 1 12 14 16 1 2 22 24 26 2 3 32 34 36 3 4 Figure S1: XRD spectra of AITF CNCs a) as received and b) Soxhlet extracted in ethanol for 24 h. 2 Green-E-Si.raw_1 a)' Counts 7 6 5 4 3 2 1 1 12 14 16 1 2 Yellow-R-Si.raw_1 22 24 26 2 3 32 34 36 1alpha cellulose 1. % 3 4 b)' 5, Yellow-E-Si.raw_1 1alpha cellulose 1. % 4, 3, 1 12 14 16 1 2 22 24 26 2 3 32 34 36 3 4 Figure S2: XRD spectra of Lab-Made CNCs a) as received and b) Soxhlet extracted in ethanol for 24 h. 3
a)' 3, Supporting Information Orange-R2-Si.raw_1 1alpha cellulose 1. % 2,5 1,5 5 1 12 14 16 1 2 22 24 26 2 3 32 34 36 3 4 b)' 2,5 Orange-E2-Si.raw_1 1alpha cellulose 1. % 1,5 5 1 12 14 16 1 2 22 24 26 2 3 32 34 36 3 4 Figure S3: XRD spectra of CelluForce CNCs a) as received and b) Soxhlet extracted in ethanol for 24 h. a)' 2,5 Pink-R-Si.raw_1 1alpha cellulose 53.9 % Cellulose II 46.11 % Counts 1,5 5 b)' 3, 1 12 14 16 1 2 22 24 26 2 Pink-E-Si.raw_1 3 32 34 36 3 4 1alpha cellulose 74.19 % Cellulose II 25.1 % 2,5 1,5 5 1 12 14 16 1 2 22 24 26 2 3 32 34 36 3 4 Figure S4: XRD spectra of FPL CNCs a) as received and b) Soxhlet extracted in ethanol for 24 h. 4
Thermal Stability Thermal Gravimetric Analysis. Thermal gravimetric analysis (TGA) was performed using TA Instruments Q5 thermal analyzer under a constant 1 ml/min argon flow. A minimum of 1 mg of freeze-dried as received and Soxhlet extracted CNCs were heated to 6 C at heating rate of 1 C/min. 1" Lab-Made"as"Received" Lab-Made"Soxhlet"Extracted" " Percent'Mass' 6" 4" 2" " 1" 15" 2" 25" 3" 35" 4" 45" 5" Temperature'( C)' Figure S5: TGA curves of as received and Soxhlet extracted Lab-Made CNCs. 1" CelluForce"as"Received" CelluForce"Soxhlet"Extracted" " Percent'Mass' 6" 4" 2" " 1" 15" 2" 25" 3" 35" 4" 45" 5" Temperature'( C)' Figure S6: TGA curves of as received and Soxhlet extracted CelluForce CNCs. 5
1" FPL"as"Received" FPL"Soxhlet"Extracted" " Percent'Mass' 6" 4" 2" " 1" 15" 2" 25" 3" 35" 4" 45" 5" Temperature'( C)' Figure S7: TGA curves of as received and Soxhlet extracted FPL CNCs. 1" " AITF"as"Received" AITF"Soxhlet"Extracted" So>wood"AITF" Percent'Mass' 6" 4" 2" " 1" 15" 2" 25" 3" 35" 4" 45" 5" Temperature'( C)' Figure S: TGA curves of as received and Soxhlet extracted cotton AITF CNCs and as received softwood AITF CNCs. 6
Changing Source and Production Scale 3, 2,5 AITF-RAW-SiBlank.raw_1 1beta cellulose 1. % 1,5 5 1 12 14 16 1 2 22 24 26 2 3 32 34 36 3 4 Figure S9: XRD spectra of as received AITF CNCS extracted from bleached softwood pulp. Other Nanocellulose Producers 2, 2,6 2,4 2,2 1, 1,6 1,4 1,2 6 4 2 AR-C-RAW-SiBlank.raw_1 1beta cellulose 1. % 1 12 14 16 1 2 22 24 26 2 3 32 34 36 Figure S1: XRD spectra of as received API s BioPlus Crystals 3 4 3, BLUEGOOSE-RAW-SiBlank.raw_1 1beta cellulose 1. % 2,5 1,5 5 1 12 14 16 1 2 22 24 26 2 3 32 34 36 3 4 Figure S11: XRD spectra of as received Blue Goose Biorefineries BGB Natural nanocellulose 7
14" 12" 1" Mean%Intensity%(%)% " 6" 4" 2" " 1" 1" 1" 1" Apparent%Par2cle%Size%(nm)% Figure S12: Apparent particle size distribution of Blue Goose Biorefineries BGB Natural as measured by DLS References [1] U. P. Agarwal, S. a. Ralph, R. S. Reiner, and C. Baez, Probing crystallinity of never-dried wood cellulose with Raman spectroscopy, Cellulose, vol. 23, no. 1, pp. 125 1, Feb. 216. [2] Y. Nishiyama, P. Langan, and H. Chanzy, Crystal structure and hydrogen-bonding system in cellulose Ibeta from synchrotron X-ray and neutron fiber diffraction., J. Am. Chem. Soc., vol. 124, no. 31, pp. 974 2, Aug. 22. [3] S. Park, J. O. Baker, M. E. Himmel, P. a Parilla, and D. K. Johnson, Cellulose crystallinity index: measurement techniques and their impact on interpreting cellulase performance, Biotechnol. Biofuels, vol. 3, no. 1, p. 1, 21. [4] A. D. French and M. Santiago Cintrón, Cellulose polymorphy, crystallite size, and the Segal Crystallinity Index, Cellulose, vol. 2, no. 1, pp. 53 5, 213. [5] C. Driemeier and G. a. Calligaris, Theoretical and experimental developments for accurate determination of crystallinity of cellulose i materials, J. Appl. Crystallogr., vol., no. 1, pp. 14 192, 211. [6] R. P. Oliveira and C. Driemeier, CRAFS: A model to analyze two-dimensional X-ray diffraction patterns of plant cellulose, J. Appl. Crystallogr., vol. 46, no. 4, pp. 1196 121, 213. [7] C. Driemeier, Two-dimensional Rietveld analysis of celluloses from higher plants, Cellulose, vol. 21, no. 2, pp. 165 173, Apr. 214. [] P. Ahvenainen, I. Kontro, and K. Svedström, Comparison of sample crystallinity determination methods by X-ray diffraction for challenging cellulose I materials, Cellulose, vol. 23, no. 2, pp. 173 16, Apr. 216.