Dielectric properties of woody hemp core, a lignocellulosic resource: variation with hemicelluloses content

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1 COST FP0802 : Hierarchical structure and mechanical characterization of wood Helsinki, August Dielectric properties of woody hemp core, a lignocellulosic resource: variation with hemicelluloses content Mohamad Eid Rahime Bag, Bernard Kurek & Johnny Beaugrand French National Institute for Agricultural Research Reims, France

2 Outline Material of study Context Strategy Methods Dielectrical analysis Preparation of samples Enzymatic degradation of hemicelluloses Results Conclusions Mohamad EID 2

$Mohamad EID 3 Mass fraction (Dry material) Wood$

3 Material of study : woody hemp core Hemp, stem structure Secondary fibers Wood Primary fibers Mohamad EID 3 Mass fraction (Dry material) Wood Celluloses 44 Hemicelluloses 18 Pectins 4 Lignins 28 (Bag 2010)

Material of study : woody hemp core Viscoelastic properties of wood Cell wall Celluloses Hemicelluloses Pectins Lignins Property Highly ordered Amorphous Amorphous Amorphous (EMPA, Sell,

4 Material of study : woody hemp core Viscoelastic properties of wood Cell wall Celluloses Hemicelluloses Pectins Lignins Property Highly ordered Amorphous Amorphous Amorphous (EMPA, Sell, Zimmermann, 1993) Glassy Transition vitreuse Transition vitreuse Glass transition, Tg Increase the efficiency of wood utilization Influence technological transformation Rubbery Fusion Fusion Mohamad EID 4

Context : characterization and identification Recently 1960 Tg measurement only on extracted wood polymers (Hemicelluloses, lignin and amorphous cellulose) Several techniques for detecting

5 Context : characterization and identification Recently 1960 Tg measurement only on extracted wood polymers (Hemicelluloses, lignin and amorphous cellulose) Several techniques for detecting transitional behavior (DMA, DSC and DETA); limited ability to the whole wood 1998 Observation of one signal = attribution to the softening of in situ lignin In wood more than one amorphous component = more than one glass transition may be observed Dielectric thermal analysis (DEA) to determine the glass transition of in situ hemicelluloses Mohamad EID 5

Context : characterization and identification Dielectric

within polymers However : Ambiguity with the assignment of in

follow how varying the hemicelluloses signal in relation with

6 Context : characterization and identification Dielectric analysis (DEA) : Exploring molecular phenomena relaxations within polymers However : Ambiguity with the assignment of in situ hemicelluloses signal - Tg in woody material We will follow how varying the hemicelluloses signal in relation with their contents in woody hemp core to certified Tg assignment. Mohamad EID 6

7 Strategy Untreated Woody hemp core - Aim : reference signal DEA comparative analysis of signal Treated woody hemp core -Aim: Modulation of hemicelluloses - How?: Enzymatic degradation High-performance liquid chromatography (HPLC) - Measure the hemicelluloses extraction impact Mohamad EID 7

Methods : Dielectric analysis (DEA) Amplitude sample Electrode Measure the electrical properties Information on : capacitive nature conductive

8 Methods : Dielectric analysis (DEA) Amplitude sample Electrode Measure the electrical properties Information on : capacitive nature conductive nature T g Applying a sinusoidal voltage to create an alternating electric field Induced dipole Phase difference δ Voltage Current Time Mohamad EID 8

Tan Tan Delta Methods : Dielectric analysis (DEA) 4 3 f = 0.5 f = 1 f = 5 f = 10 Y = 2E+11e -6.553X R 2 =0.

9 Tan Tan Delta Methods : Dielectric analysis (DEA) 4 3 f = 0.5 f = 1 f = 5 f = 10 Y = 2E+11e X R 2 = Peak of tan δ = Tg (f = 1Hz) Universal V4.3A TA Instruments Temperature ( C) Arrhenius formula : Slope of Mohamad EID 9

10 Methods : Samples preparation X 3 One stick of hemp core originating from the stem W A B C D Water reference 540 min R Treatment by enzymatic cocktail 15 min A 30 min B 60 min C 540 min D 2 days at constant humidity (63% Relative Humidity) HPLC : - Quantification and qualification of hemicelluloses extracted Liquid phase Solid phase Dielectric analysis (DEA): - Studying signals to compare recorded glass transition Mohamad EID 10

11 Methods : Hemicelluloses modulation Enzymatic degradation 7 types of enzyme β-mannanase α-l-arabinanase Pectinase Endo-1,4 β-xylanase Pectinesterase Arabinofuranosidase Endo-1,4 β-d-galactanase HPLC Cell wall Mohamad EID 11

12 Methods : HPLC Galacturonic acide Glucoronic acide Analytical column Chromatogram : integration identification of components + Enzymatic cocktail Mixture + H 2 SO 4 Peak of conductivity: proportional to the concentration of the eluted component. Fucose Detector Mohamad EID 12

13 Tan Delta Dielectric loss tangent (tan Delta) Results : dielectric relaxation Frequency 1 Hz 11 9 Raw woody hemp core (0% of degradation) Water reference (0.02 % ) 15 min of treatment by enzymatic cocktail (11%) 30 min of treatment by enzymatic cocktail (18%) 60 min of treatment by enzymatic cocktail (19%) 540 min of treatment by enzymatic cocktail (20%) Temperature ( c) Mohamad EID 13 Temperature ( C) Temperature ( c) Universal V4.3A TA I

14 Results : hemicelluloses degradation % of Hemicelluloses degradation 80 25% 60 20% ΔTg 15% 0 Degradation of of hemicelluloses 10% % -60 0% Enzymatic degradation time in minute Enzymatic degradation : very quick during the first 15 minutes maximum level in 1 hour Mohamad EID 14

15 Hemicelluloses Tg in C Results : Glass transition variation % of Hemicelluloses degradation 80 25% % 20 0 ΔTg Degradation of hemicelluloses 15% 10% % -60 0% Enzymatic degradation time in minute Tg variation according to DEA signals : strong impact of the hemicelluloses degradation similar variation trend as hemicelluloses degradation Mohamad EID 15

16 Tan δ Results : intensity of peaks variation % of Hemicelluloses degradation % % Intensity of peaks attributed to hemicelluloses 15% 150 Degradation of hemicelluloses 10% % % Enzymatic degradation time in minute Intensity of peaks variation : strong impact of the degradation on the intensity Mohamad EID 16

Conclusions Efficiency of the modulation of hemicelluloses by enzymes A relationship between in situ hemicelluloses : and the variation of the Tg measured by DEA and intensity of

17 Conclusions Efficiency of the modulation of hemicelluloses by enzymes A relationship between in situ hemicelluloses : and the variation of the Tg measured by DEA and intensity of the dielectric relaxation response This work demonstrates that DEA technique is suitable to measure the Tg of hemicelluloses and the structure variation around them Mohamad EID 17

Thank you for your attention Mohamad EID Materials technology engineer mohamad.

fr PhD student at INRA - (French National Institute for Agricultural Research) UMR

18 Thank you for your attention Mohamad EID Materials technology engineer PhD student at INRA - (French National Institute for Agricultural Research) UMR FARE - Material Team Bldg. 18, Moulin de la Housse, BP Reims Cedex 2 Office: Fax: Mohamad EID 18

Relationships between biochemistry, modulation of cell wall viscoelastic properties and fracture behaviour in woody hemp core by correlation study

$Relationships between biochemistry, modulation of cell wall viscoelastic properties and fracture behaviour in woody hemp core by correlation study$ Relationships between biochemistry, modulation of cell wall viscoelastic properties and fracture behaviour in woody hemp core by correlation study Rahime BAG INRA Reims UMR FARE 2, esplanade Roland Garros