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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) [email protected] IFAT 2010 - Muenchen 17.September 2010 Geographic reasons Slovenia 58.4% of surface is forest. Forest is spreading! IFAT 2010 - Muenchen 17.September 2010 Lignocellulosic biomass Cellulose hemicellulose Glucose Xylose, Arabinose Ethanol Fuels IFAT 2010 - Muenchen Organic acids, textile fibers, polymers, adhesives, lubricants, inks lignin Polymers, fuels 17.September 2010 Lignocellulose-based materials IFAT 2010 - Muenchen 17.September 2010 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 IFAT 2010 - Muenchen 17.September 2010 What is LIQUID WOOD ? A blend of depolymerized and 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 IFAT 2010 - Muenchen 17.September 2010 Liquefaction mechanism • Wood is a complex composite of: - highly crystalline cellulose - polyphenolic lignin - hemicelluloses - minerals, resins etc. 42 - 51% 18 – 30% 24 – 40% •Polysaccharides → glucoside→ levulinic ester IFAT 2010 - Muenchen 17.September 2010 Liquefaction mechanism •Lignin → benzyl cation → reaction intermediates → glycol ethers of depolimerized segments → condensation products IFAT 2010 - Muenchen 17.September 2010 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) - 300 g glycol (glycerol, diethylene glycol) - 12 g acid catalyst ( pTSA) • Product analysis: - gravimetric determination of remaining wood - FTIR, GPC analysis - OH value determination IFAT 2010 - Muenchen 17.September 2010 Liquefaction product IFAT 2010 - Muenchen 17.September 2010 Liquefaction product IFAT 2010 - Muenchen 17.September 2010 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. IFAT 2010 - Muenchen 17.September 2010 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 IFAT 2010 - Muenchen 17.September 2010 SYNTHESIS OF LINEAR, SATURATED POLYESTERS FOR POLYURETHANE FOAMS Mn Dalton LW 300g LW, 60g AA 300g LW, 60g PAA 300g LW, 30g AA, 30g PAA IFAT 2010 - Muenchen OH value mgKOH/g Viscosity Pa.s 19400 1043 3.0 24.5 39900 798 1.9 22.7 60000 378 1.8 23.3 79500 437 2.1 23.1 Mw Dalton % of wood (w/w) 4790 10300 4590 7980 17.September 2010 SYNTHESIS OF POLYURETHANE FOAMS FOAM PREPARATION: COMPONENTS: Parts by Weight Liquefied wood Catalysts 100.0 KOC DMEA 2.0 2.5 Silicone surfactant 1.5 Water, ethanol, hexane 3.0 PMDI* 180.0 PMDI : diphenylmethane diisocyanate polymer DMEA: N,N-Dimethyl ethanolamine KOC: potassium octoate IFAT 2010 - Muenchen 17.September 2010 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 Addition of glycerol IFAT 2010 - Muenchen 17.September 2010 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 IFAT 2010 - Muenchen 17.September 2010 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! IFAT 2010 - Muenchen 17.September 2010 PANEL BOARD PRODUCTION - OPPORTUNITIES Global Panel board production 2011: 75 Mio m3 – Europe:37 Mio m3 – Asia: 32 Mio m3 37 Mio m3: 17 12 4 4 Mio m3 particle board Mio m3 MDF (Medium density fiber board) Mio m3 Plywood boards Mio m3 OSB (Oriented strand boards) 10% Adhesive 30% Adhesive ~15% Adhesive 5% Adhesive 17 Mio m3 = 12 Mio Tons = 1.2 Mio Tons of adhesive IFAT 2010 - Muenchen 17.September 2010 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. IFAT 2010 - Muenchen 17.September 2010 SINGLE LAYER PARTICLE BOARD Standard adhesives: Melamine –formaldehyde, melamine – urea – formaldehyde resins Hot pressed at 180° C, 3 N/mm2, for 5 minutes IFAT 2010 - Muenchen 17.September 2010 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. Required values Achieved values Meldur H-97 Achieved values Meldur MS-1 16,0 ± 0,3 16.1 16.2 - 0.68 0.67 Above 0.35 0.40 0.49 Surface soundness EN 311 (N/mm2) Above 0.8 1.0 0.9 Bending strength EN 310 (N/mm2) Above 13 15.9 16,5 Swelling in Thickness EN 317 (%) Below 15 11.6 15.9 Below 8 5.7 3.6 Board thickness EN 324 (mm) Density EN 323 (g/cm3) Internal bond strength EN 319 (N/mm2) Formaldehyde release Perforator method EN 120 (mg/100g board) IFAT 2010 - Muenchen 17.September 2010 THREE - LAYERS PARTICLE BOARD Standard adhesives: Melamine – formaldehyde, melamine – urea – formaldehyde resins Hot pressed at 180° C, 3 N/mm2, for 5 minutes IFAT 2010 - Muenchen 17.September 2010 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 Required values Achieved values 16,0 ± 0,3 16.1 - 0.72 Above 0.35 0.94 Surface soundness EN 311 (N/mm2) Above 0.8 1.96 Bending strength EN 310 (N/mm2) Above 13 21.1 Swelling in Thickness EN 317 (%) Below 15 8.2 Below 8 3.2 Board thickness EN 324 (mm) Density EN 323 (g/cm3) Internal bond strength EN 319 (N/mm2) Formaldehyde release Perforator method EN 120 (mg/100g board) IFAT 2010 - Muenchen 17.September 2010 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 IFAT 2010 - Muenchen 17.September 2010 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 IFAT 2010 - Muenchen 17.September 2010 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% IFAT 2010 - Muenchen 17.September 2010 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. IFAT 2010 - Muenchen 17.September 2010 Future: • Liquefaction with the use of the ULTRASOUND • Liquefied wood – MUF adhesives: new applications • Energy source and fuel • Effective wood waste recycling IFAT 2010 - Muenchen 17.September 2010 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 IFAT 2010 - Muenchen 17.September 2010