Phosphorylation of nanocellulose and its application potencials. Selestina Gorgieva, Mojca Božič, Robert Vogrinčič, Vanja Kokol *

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1 Phosphorylation of nanocellulose and its application potencials Selestina Gorgieva, Mojca Božič, Robert Vogrinčič, Vanja Kokol * CST action 1205, Iasi, Romunia, March

2 AIM To compare enzymatic vs. chemical (hetero /homo geneously via hydrohyls, via carboxyls) phosphorylation (introd. anionic phosphate ester gr. P 3 ) approaches of cellulose nanofibrils (CNF) and cellulose nanocrystals (CNC) To characterize phosphorylation efficacy and stability To establish structure morphology properties relationship To utilize phosphorylated properties potential applications 2

3 Enzymatic vs. Chemical (on Cell H / CH groups) Hexokinase mediated vs. By using H 3 P 4 using ATP/Mg 2+ in water or molten urea 13 C NMR spectroscopy Phosphorylation occurred at C6 H group of the glucose, resulting to minor crystal structure reduction. 13 C NMR spectroscopy Phosphorylation occurred at C6, C2 and/or C3 H groups of the glucose, resulting to huge crystal structure reduction. ATR FTIR spectroscopy Two IR bands at 2360 cm 1 (P H) 1210 cm 1 (P=) Tautomeric equilibrium The same structure of functional groups confirmed by both process! ph H P Mg2+ H Phosphorylated CNF at 250 mm MgCl 2 n Potentiometric titration Two inflexion points in the ratio of 1:2 Di basic acid behavior EDTA, NaH, ph ml 2 hours, 25 C H P 2.4 ml H n V(base), ml 3

4 Quatification & stability of P 3 groups / CNF ( P 3 ) mmol/kg ( C ) mmol/kg CNC ( P 3 ) mmol/kg ( C ) mmol/kg REF 0 73± ±6 Enzymatic Hex+ATP 154±11 nd nd nd Expensive & in reusable Hex/ATP Difficulty washed out ATP no effect on crystallinity Chemical on H gr. H 3 P 4 /water 18±2 Confirmed 435±7 H 3 P 4 /molten urea 1173±26 by FTIR 1038±9 Di and tri substituted esters with CNF can be formed, yielding to insoluble products. No changing in crystalline structure. HYDRLYSIS is pronounced at high molar (>10mM) acidic (ph<3, HCl) or alkaline (ph>8, NaH) mediums. Chemical via CH gr Very stable linkage Reusable treating bath (monomers) BŽIČ, Mojca, LIU, Peng, MATHEW, Aji P., KKL, Vanja. Enzymatic phosphorylation of cellulose nanofibers to new highly ions adsorbing, flame retardant and hydroxyapatite growth induced natural nanoparticles. Cellulose, Aug. 2014, vol. 21, iss. 4, str Vanja KKL, Mojca BŽIČ, Robert VGRINČIČ, Aji P. MATHEW, Characterization and properties of homo and heterogenously phosphorylated nanocellulose, Carbohydrate Polymers, CARBPL D , sibmitted.

Size (nm) vs. Z potential (mv) P CNFs/CNCs form well dispersed particles between ph 4.5 10.5. pk 1 (ph 7.3) : CNF P 3 H 2 CNF P 3 H pk 2 (ph 12.

5 Size (nm) vs. Z potential (mv) P CNFs/CNCs form well dispersed particles between ph pk 1 (ph 7.3) : CNF P 3 H 2 CNF P 3 H pk 2 (ph 12.5) : CNF P 3 H 2 CNF P 3 Size (nm) Z potential (mv) 0 ph 4,5 ph 7,5 ph 10,5 ph 12,5 Native CNF Phosph CNF Native CNC Phosph CNC Native CNF Phosph CNF 50 Charge [mmol/g] 0,0-0,5-1,0-1,5 4CNF+4CMC 4CNF-CH-Apa+4CMC 4CNF-CH-Aln+4CMC P 3 2- (pka2) pcnf shown an increased adsorption capacity towards more alkaline region (ph > 7) -2,0-2,5 1m m -3,0 C - P 3 2- (pka1) ph

Flame retardant properties (biobased nano composites) Weight loss[%] 100 80 60 40 20 0 Native CNF Phosph

7M H3P4)" Phosph CNF (Molten urea+h3p4) Phosph CNF HEX (250mM MgCl2) 0 100 200 300 400 500 600

6 Flame retardant properties (biobased nano composites) Weight loss[%] Native CNF Phosph CNF (10.7M H3P4)" Phosph CNF (Molten urea+h3p4) Phosph CNF HEX (250mM MgCl2) Temperature [ C] Heat Flow (mw), (Exo up) Native CNF Phosph CNF (10.7M H3P4) Temperature [ C] Native CNF Phosphorylated CNF 10 µm I I 10 µm I I

7 Biomineralization potential (hydroxyapatite growth) after 10 days of exposure to simulated body fluid (SBF) at 37 C Native CNF Phosphorylated CNF 10 µm I I 10 µm I I GEL alignment induced by CNF self - assembling Gelatin+CNF 250 µm 40 µm 4 w e e k s M I N E R A L I Z A T I N 40 µm Gelatin+p-CNF 40 µm 250 µm pcnf-orientation is disturb after mineralization Mineralization process is induced by pcnf presence and location 7

8 High and selective adsorption of heavy metals & cationic dyes Ion exchange filtration performance Des. 69% Adsorption kinetic [%] 80 1m m pen porous system on top, in cross section & on bottom Des. 99% Des. 99% Des. 99% 40 P_7CNF+/1CMC Des. 75% 7CNF+1CMC 20 P_4CNF+4CMC Des. 75% 4CNF+4CMC 0 0,1 1 time (h)

9 CNCLUSINs The enzyme mediated phosphorylation of NC was confirmed, resulting to very low SD, and inability of regeneration of very expensive ATP as well as cofactor (Mg 2+ ). Chemically phosphorylated approach (esterification) using H3P4 in heterogeneous (in water) and homogeneous (in molten urea) conditions, yielding a CNF with much higher charge densities, but lower stability in highly molar (>10mM) acidic (ph<3) or alkaline (ph>8) mediums. Very stable chemical phosphorylation of CNF via CH groups using Apa/Aln molecule (bearing one/two phosphate group s) was examined, showing an enlarged intrinsic adsorption potential towards positively charged molecules (e.g. cationic dyes and metals) in more alkaline region (ph > 7). New application potencials (filtration, composite, biomedical) are confimred. 9

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