Liquefied Wood – a source of raw materials

1. Liquefied Wood – a source of raw materials Asist.Prof.Dr. Matjaž Kunaver National Institute of Chemistry, Ljubljana, SLOVENIA And Center of Excellence for Polymer Materials and Technologies (PoliMaT) matjaz.kunaver@ki.si

2. Geographic reasons Slovenia 58.4% of surface is forest. Forest is spreading!

3. Lignocellulosic biomass Cellulose hemicellulose lignin Glucose Xylose, Arabinose Organic acids, textile fibers, polymers, adhesives, lubricants, inks Ethanol Fuels Polymers, fuels

4. Lignocellulose-based materials

5. Experimental approach Unseparated wood (polymers) to undergo partial depolymerization with polyols to obtain complex multifunctional oligomeric mixture – feedstocks for polymer synthesis: Polyesters: unsaturated and saturated Polyurethanes

6. What is LIQUID WOOD ? A blend of depolymerizedand solubilized wood components obtained by reaction with polyhydric alcohols in the presence of acid as a catalyst. Liquefaction converts wood into a feedstock for the new, environmentally friendly polymers

7. Liquefaction mechanism • Wood is a complex composite of: • highly crystalline cellulose 42 - 51% • polyphenolic lignin 18 – 30% • hemicelluloses 24 – 40% • minerals, resins etc. • Polysaccharides→ glucoside→ levulinic ester

8. Liquefaction mechanism • Lignin • →benzyl cation • → reaction intermediates • → glycol ethers of • depolimerized segments • → condensation products

9. Liquefaction process • Glass reactor with external heating, mixing • - 0.5 to 3 hours at 150 - 180 oC • Typical reaction mixture: • - 100 g wood (or lignocellulosic material) • - 300g glycol (glycerol, diethylene glycol) • - 12 g acid catalyst (pTSA) • Product analysis: • - gravimetric determination of remaining wood • - FTIR, GPC analysis • - OH value determination

10. Liquefaction product

11. Liquefaction product

12. Hydroxyl content in the liquefied spruce wood samples, taken at different time intervals. OH groups are spent during the liquefaction reaction: - Formation of ester and ether bonds with glycols.

13. Polyester resins from liquefied wood The main goal: to synthesize a poliester with higher molar mass than the liquefied wood and with the same functionality as the commercial one. A typical formulation: - 300g of neutralized liquefied wood - 60g of adipic acid - 0.1g of dibutyl tin oxide Temp: 190-220oC , reaction time: approx. 4 hours

14. SYNTHESIS OF LINEAR, SATURATED POLYESTERS FOR POLYURETHANE FOAMS

15. SYNTHESIS OF POLYURETHANE FOAMS FOAM PREPARATION: PMDI : diphenylmethane diisocyanate polymer DMEA: N,N-Dimethyl ethanolamine KOC: potassium octoate

16. Addition of glycerol SYNTHESIS OF POLYURETHANE FOAMS Polyurethane foams based on liquid wood poliols,Density = 0.03 -0.05 g/ cm3 Compressive strength at 10% strain: 46kPa – 74kPa Thermal conductivity: 0.036 W/mK

17. SYNTHESIS OF POLYURETHANE FOAMS Properties of polyurethane foams differ depending on the variations of the linear polyester formulation as well as final foam formulation. Pigments for coloration, additives to improve durability can easily be incorporated into the final foam formulation. Wood content: - 50% - 25 % in liquefied wood - 45% - 25% in linear polyester - 20% - 10% in polyurethane foam

18. Wood content: a practical example 75 pairs of disposable chopsticks give 500gr of wood and together with alcohols -> 1000gr of LIQUEFIED WOOD (50% wood content). From 1000gr of L.W. we can synthesize 1170gr of LINEAR POLYESTER (still 43% of wood) From 1170gr of polyester with addition of PMDI, 2930gr of rigid POLYURETHANE FOAM can be prepared (17% of wood ) 2930gr of PUR = 58 Lit of volume! 1 chopstick gives 0.78 Lit of PUR foam! 1 chopstick with wrap paper gives 0.90 Lit of PUR foam!

19. Global Panel board production 2011: 75 Mio m3 Europe:37 Mio m3 Asia: 32 Mio m3 37 Mio m3: 17 Mio m3 particle board 10% Adhesive 12 Mio m3 MDF (Medium density fiber board) 30% Adhesive 4 Mio m3 Plywood boards ~ 15% Adhesive 4 Mio m3 OSB (Oriented strand boards) 5% Adhesive 17 Mio m3 = 12 Mio Tons = 1.2 Mio Tons of adhesive PANEL BOARD PRODUCTION - OPPORTUNITIES

20. Liquefied wood, paper, bark – adhesives for plywood and wood chip panels Standard adhesives: Melamine –formaldehyde resins, melamine – urea – formaldehyde resins Up to 50% of adhesive can be replaced with liquefied wood. The temperature can be lowered to 160° C. Formaldehyde release: less than 5mg/100g European standard EN 312:2003 compliant.

21. SINGLE LAYER PARTICLE BOARD Standard adhesives: Melamine –formaldehyde, melamine – urea – formaldehyde resins Hot pressed at 180° C, 3 N/mm2, for 5 minutes

22. Liquefied wood, paper, bark – adhesives for plywood and wood chip panels Mechanical and physical properties of particle boards prepared using an adhesive that contained the addition of 50 % (w/w) liquefied spruce wood.

23. THREE - LAYERS PARTICLE BOARD Standard adhesives: Melamine –formaldehyde, melamine – urea – formaldehyde resins Hot pressed at 180° C, 3 N/mm2, for 5 minutes

24. Mechanical and physical properties of particle boards prepared using an adhesive that contained the addition of 30 % (w/w) liquefied spruce wood – industrial process simulation

25. Liquefied wood – polyester: adhesives for plywood panels A combination of polyester based on liquefied wood with a melamin-formaldehyde resin (1:1 ratio). POLYESTER: 500g L.W. 50g APA 0.3g F4201 4.5 hours at 180oC-220oC OH value: 333.5mgKOH/g

26. Liquefied wood – polyester: adhesives for plywood panels A combination of polyester based on liquefied wood with a melamin-formaldehyde resin (1:1 ratio). STANDARD EN 12765: Classification of thermosetting wood adhesives for non-structural applications... More than 12N/mm2 of the bond strength can be achieved. CLASS C1 and C2 compliant

27. Liquefied wood – liquid fuel Liquid fuel with more than 22 MJ/kg heat of combustion (brown coal: 14 MJ/kg, dry wood: 15 MJ/kg) High viscous liquid at room temperature (3 Pa.s), but soluble in ethanol. Sulfur content: 0.25%

28. Conclusions • Different lignocellulosic materials were liquefied with yields higher than 95%, (Lignin – with additional use of the ultrasound). • Polyesters were synthesized using liquefied wood, waste paper or other lignocellulosic materials as a feedstock where liquefied wood/paper replaced a certain amount of polyhydric alcohols – produced form crude oil. • The properties of polyurethane foams were similar to commercially available samples. • Liquefied lignocellulosic materials were used as adhesives for particle boards production – with reduced formaldehyde emission and excellent mechanical properties. • Efficient lignocellulosic waste recycling and use of renewable resources, including glycerol from biodiesel production.

29. Future: • Liquefaction with the use of the ULTRASOUND • Liquefied wood – MUF adhesives: new applications • Energy source and fuel • Effective wood waste recycling

30. Acknowledgments: • Authors wish to gratefully acknowledge the support for the presented work received from: • Ministry of Higher Education, Science and Technology of the • Republic of Slovenia within Program P2-0145 and through the • contract No. 3211-10-000057 (Center of Excellence Polymer • Materials and Technologies). • Colleagues at the Polymer chemistry and technology laboratory • GGP for their financial and material support, • Melamin, for their general help and material support