Ionic Liquids : Green Process for Modifying Nanofibrillated Cellulose Surface Chemistry

Transcription

1 Ionic Liquids : Green Process for Modifying Nanofibrillated Cellulose Surface Chemistry Karim Missoum, Mohamed Naceur Belgacem, Julien Bras*, INP SUNPAP Workshop *julien.bras@pagora.grenoble-inp.fr

2 Laboratory of Pulp and Paper Science (LGP2 UMR 5518) 2

3 SUNPAP rganization WP0 : Coordination WP11 : Dissemination and IPR WP1 : Market needs Module 1 : Value chain WP2 : Sustainability assessments WP3 : Recyclability / biodegradability Module 2 : NFC production Module 2 : NFC processing WP4 : NFC production WP5 : NFC Functionalization SSCCP, CTP, INP, KaU, UAVR, Colorobbia Module 4 : Health and safety WP6 : NFC application WP7 : Scale modeling WP8 : Demonstration WP9 : Toxicity WP10 : Risk assessment 3

4 UTLINES Ionic Liquids : Green Process for Modifying Nano- fibrillated Cellulose Surface Chemistry I. NFC and Ionic Liquids : Introduction II. Materials & Methods III. Results & Discussions : Efficiency of grafting IV. Conclusions & Perspectives 4

5 Nanocellulose : Definition NFC Improvements Gelly-like structure Mechanical properties Barriers properties 100 nm EHT = 3.00 kv Grenoble INP CMTC Missoum et al. INP - CMTC, 2010 Pääkkö, et al. Biomacromolecules, 2007, 5

6 From Fibers to Nanocelluloses Fiber 2 to 10 m².g -1 x10 NFC 51 m².g -1 Drawbacks 1% accessible 3,1% accessible Impossible to use industrially Coating / extrusion etc Agglomeration Gel very low when concentration dried Difficult to re-disperse Poor compatibility with hydrophobic polymers 2% wt Siqueira, Bras et al. (Langmuir 2010) 6

7 Proof of concept Strategy : - Limit hydrogen interactions with water by chemical modification H H R R R R Project requirement : - Limit the use of organic solvent - Development of green processes INIC LIQUIDS 7

8 Ionic Liquids (IL) Ionic Liquids (IL) composed of anionic and cationic part 2 main families of cation : imidazolium / pyridinium moieties R2 N + N R1 + N R R 1 =aliphatic chain (C 2,C 6,C 8 ) R 2 = CH 3,CH 2 CH 3 ) R=aliphatic chain (C 2,C 6,C 8 ) Described as green solvents : Immeasurable vapor pressure = N Volatile rganic Compounds (VC) Thermal stability, nonflammability, Ionic conductivity Easily RECYCLABLE 8

9 Tomorrow Today Cellulose and Ionic Liquids Mainly used for solubilization or homogeneous chemical modification (T. Heinze, T. Libert, 2008) New interest in cellulose degradation for obtaining nanocellulose (Z. Man et al., June 2011, Journal of Polymers and the Environment) Degradation and Swelling of Cellulose To avoid these phenomena : use of a nonpolar IL 1-butyl-3-methylimidazolium hexafluorophosphate No papers dealing with heterogeneous chemical modification of NFC 9

10 UTLINES Ionic Liquids : Green Process for Modifying Nano- fibrillated Cellulose Surface Chemistry I. NFC and Ionic Liquids : Introduction II. Materials & Methods III. Results & Discussions : Efficiency of grafting IV. Conclusions & Perspectives 10

11 Materials : NFC SEVERAL KINDS F NFC : Be very precise about preparation Industrial Bleached Sulphite Domsjö pulp (mix Pinus and Spruce) Mechanical Refining Enzymatic Treatment Homogenizer : Microfludizer Bleached Sulphite Pulp (BSP) Mechanical refining Refining BSP Cellulase Treatment (50 C 2h) Refined & Enzymaticaly Treated BSP Homogenizing Microfludizer NFC 11

12 Chemical Reaction H * n H H Cellulose + i Acetic Anhydride (AA) R * R R R R p Cellulose stearate * R = C-(CH 2 ) 16 -CH R 3 or H depending on the DS Butyric Anhydride (BA) iso-butyric Anhydride (i-ba) R1 R R R + R p Modified cellulose Acid form ii * R N H Hexanoic Anhydride (HA) R R R R p R (=C-R1) or H depending on the DS R1 (CH 3 ), (CH 2 ) 2 CH 3, CH(CH 3 ) 2 or (CH2) 4 CH 3 (AA) (BA) (i-ba) (HA) Cellulose octadecylcarbamate or H depending on the DS R = C-NH-(CH 2 ) 17 -CH 3 12

13 Procedure : Native Fibers Native NFC (in water) Centrifugation cycles to remove water Native NFC (in acetone) T = 80 C T = 100 C Native NFC (in bmimpf 6 ) Acetone Bmim PF 6 By products 2h 100 C Grafting (AA, BA, i-ba or HA) Grafted NFC FILTRATIN IL + by product + reagent Liquid / liquid extraction Na Ethylic ether 24h of soxhlet extraction : ethanol / dichloromethane (1/1v) 13

14 Procedure : Native Fibers Native NFC (in water) Centrifugation cycles to remove water T = 80 C Native NFC (in acetone) T = 100 C Native NFC (in bmimpf 6 ) Acetone Bmim PF 6 By products Sustainability 2h 100 C Grafting (AA, BA, i-ba or HA) Grafted NFC FILTRATIN IL + by product + reagent Liquid / liquid extraction Na Ethylic ether 24h of soxhlet extraction : ethanol / dichloromethane (1/1v) 14

15 Methods: Proof of grafting G R A F T I N G Structural properties Characterization Recyclability of IL METHDS F CHARACTERIZATIN FEG SEM : Diameter (nm) XRD : Degree of cristallinity FTIR : Vibration of specific bonds Contact Angle : Surface energy properties Elemental Analysis : Degree of substitution (BULK analysis) XPS : Characterization of binding Energy FTIR : Detection of by products or reagents RMN : 1 H, 13 C, 19 F, 31 P 15

16 UTLINES Ionic Liquids : Green Process for Modifying Nano- fibrillated Cellulose Surface Chemistry I. NFC and Ionic Liquids : Introduction II. Materials & Methods III. Results & Discussions IV. Conclusions & Perspectives 16

17 Structural Properties : Field Emission Scanning Electron Microscopy (FE-SEM) Neat NFC : nm NFC_AA Diameter : nm NFC_BA Diameter : nm NFC_i-BA Diameter : nm NFC_HA Diameter : nm Increasing of diameter due to the grafts (working as a hydrogen bond blocking system) Nanofibers less entangled Less hydrogen interactions 17

18 Structural Properties : Increase of diameter Adapted from Berlioz et al, 2009 Neat NFC R R R R R R R R R R R R Grafted NFC 18

19 Structural Properties : X-Ray Diffraction (XRD) Samples Degree of cristallinity (%) Neat_NFC 80.2 (+- 0.5) NFC_AA 82.6 (+- 0.9) NFC_BA 80.8 (+- 0.6) NFC_i-BA 80.9 (+- 0.5) NFC_HA 80.6 (+- 0.7) No crystalline structure changes No alteration of the quality of the crystalline part after grafting 19

20 Surface Characterization : Infra Red (FTIR) NFC_HA NFC_i-BA NFC_BA NFC_AA Characteristic peaks : Apparition of n (C=) : 1730cm Slight increase of n (CH-CH2) : 2950 cm Strong diminution of n (H2) : 1650 cm -1 Neat NFC 20

21 Surface Characterization : Contact Angle (CA) C.A mesurements with water Grafted NFC Neat NFC The longer aliphatic chain, the higher contact angle value Modification of the Surface Energy Hydrophobic Surface 21

22 Bulk Characterization: Elemental Analysis (EA) Samples Experimental Values Corrected Values %C %H % %C DS NFC_AA NFC_BA NFC_i-BA CNCLUSINS Thanks to FE-SEM, XRD, FTIR, CA and EA, Samples are grafted -C= bonding? XPS analyses NFC_HA Degree of substitution constant 22

23 Surface Characterization : X-ray Photoelectron Spectroscopy (XPS) 1s C1s NFC_HA NFC_i-BA C1s Deconvolution NFC_BA NFC_AA Deconvolution leads to specific binding energy 23

24 Surface Characterization : X-ray Photoelectron Spectroscopy (XPS) Samples Experimental Values Deconvolution of C1s %C % /C C1% C2% C3% C4% Neat NFC NFC_AA NFC_BA NFC_i-BA NFC_HA where C1 = C C or C H C2 = C C3 = C or C= C4 = C= C1 and C4 increase when substrates are grafted C4 s signal reveals clearly the ester bonds Samples are grafted 24

25 Recyclability: FTIR Characterization FTIR spectra after Na and ether liquid / liquid extraction (a) IL pur and for IL recycled after (b) acetic, (c) butyric and (d) hexanoic anhydride grafting FTIR analyses show a good purification of the used IL NMR characterization to confirm the purity of the IL 25

26 NMR Characterization Recycled IL Recycled IL Ionic Liquid Recycled IL Recycled IL 26

27 UTLINES Ionic Liquids : Green Process for Modifying Nano- fibrillated Cellulose Surface Chemistry I. NFC and Ionic Liquids : Introduction II. Materials & Methods III. Results & Discussions IV. Conclusions & Perspectives 27

28 Conclusions New method to graft nanofibrillated cellulose in green solvent (No VC) Good recyclability and purification of the ionic liquid after the modification Sustainability First time in heterogeneous condition using Ionic Liquids All characterizations confirm the grafting 28

29 Perspectives Applications : Capacity to be redispersed in water? - Water re-dispersion? for coating colors? - Influence on rheological properties? - ther properties (Biodegradability / Antimicrobial) Up - scaling : - Important initial investment cost BUT RECYCLABILITY - ptimization of washing steps 29

30 THANK YU FR YUR ATTENTIN QUESTINS? The research leading to these results received funding from the European Community s Seventh Framework Programme under Grant Agreement No