Sustainable Chemistry in Wood Transformation Tatjana Stevanovic, Professor

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1 Sustainable Chemistry in Wood Transformation Tatjana Stevanovic, Professor Wood Sciences and Forestry Department, Laval University, Quebec City, Canada Wood Science and Technology, Beijing, 27-31

2 Sustainable Chemistry Green chemistry also known as sustainable chemistry, is the design of chemical products and processes that reduce or eliminate the use or generation of hazardous substances. Green chemistry applies across the life cycle of a chemical product, including its design, manufacture, and use. 12 principles of sustainable chemistry are defined Inspired by these the 12 principles of green engineering into which wood engineering is perfectly integrated We shall be exploring some of them through the case study of two selected wood transformation processes Wood Science and Technology, Beijing, 27-31

3 Prevention Instead of Treatment of Waste Principle and role of wood chemistry Sustainable chemistry principle : It is better to prevent waste than to treat or clean it up after it is formed part of wood transformation practices for a long time Word waste replaced by residue Use of sawdust, shavings, small diameter wood etc. as feedstock for wood panels and pulp and paper manufacture is a long time practice Wood Science and Technology, Beijing, 27-31

4 Wood engineering practices and biorefinery concept Biorefinery concept of wood transformation as a holistic approach to forest biomass transformation Sustainable engineering principle: Integrate Material and Energy Flows: Design of products, processes, and systems must include integration and interconnectivity with available energy and materials flows

5 Examples of biorefinery concept in wood transformation The co-generation of energy by combustion of the residues within the same mill is a common practice the multiple projects on cellulosic ethanol are proposed production of nano-cellulose from highly purified chemical pulp under development pyrolysis of forest biomass for production of biofuels The good knowledge of wood chemistry is essential for all further developments and design of innovative wood products within the biorefinery concept

6 Renewable rather than depleting: wood as raw material Sustainable chemistry principle: Material and energy inputs should be renewable rather than depleting Obviously applied by wood industry which is dealing with a renewable material Should secure its favorable position in all future developments Two innovative wood transformation processes and how the sustainable (green) chemistry and engineering principles apply to them will be reviewed NWFP based on phenolic extractives from bark Innovative technology of welding solid wood without adhesives. Wood Science and Technology, Beijing, 27-31

7 Extraction of bioactive molecules from bark and forest bioefinery Sustainable engineering principle: Design for Separation and Purification Operations: should be designed to minimize energy consumption and materials use Green (sustainable) chemistry principle: Atom Economy: Design methods to maximize the incorporation of all materials used in the process into the final product, are applied in the processes of the forest biomass extraction Contribution to atom economy by saving the bioactive molecules from residues of wood transformation, such as bark, most readily and abundantly available Polyphenols from bark

8 Bark extractives from Canadian species bark extractives available from commercial wood species of Canada real potential to integrate the extraction as part of the biorefinery concept into primary transformation of wood extraction with green solvents (primarily water and ethanol) of residual bark The extracted bark still available as source of fibers or for energy production sustainable chemistry principles by saving the atoms in the molecules so ingeniously synthesized by nature

9 Selection criteria Ethnopharmacological data Commercial importance

10 Hot water extract from black spruce bark Important antioxidant and anti-inflammatory properties NWFP- Antioxidants of natural (plant) origin High content of total phenols and flavonoids low toxicity on normal human keratinocytes adequate chemical reactivity towards different free radicals involved in psoriasis, a skin disorder affecting up to 2 % of the world s population Potential of very high value pharmaceutical application of the hot water extract of black spruce bark and its fractions

11 Ethyl-acetate fraction of hot water extract of black spruce Picea mariana bark composed of lignans, neolignans, cinnamic acids, flavonoids and stilbene resveratrol, along with minor quantities of other phenols and terpene derivatives HO 3' 4' 2' 1' β 2 3 HO 5' 6' α OH Trans-resveratrol

12 Black spruce bark- new source of resveratrol Source Resvératrol (µg.g -1 ) Dark chocolate** 0.4 Raisins variety Thompson Peanuts Black spruce bark Commercial extracts Resveratrol (mg/100 g extrait) Red wine 337 Red grape skin** White grape skin** 63 Red grape seeds** 27 White grape seeds** 25 HO 4' HO 3' 2' 5' 6' 1' β α 1 **Counet et al (2006). Food Chemistry 98 : OH Polygonum cuspitatum** Purified black spruce bark extract

13 Forest and agricultural resources belong to the same world- better synergy needed Trans-resveratrol concentration in black spruce bark 109 mg/g, while in grapes only 40 mg/g Black spruce bark an interesting alternative source of this valuable bioactive molecule Further study: Crude water extract of black spruce bark obtained on a larger scale same chromatographic profile and the comparable contents of the total phenols constituents

14 Black spruce bark water extract and its fractions The crude water extract examined in form of powder on rats: does not have any adverse effects as demonstrated by acute toxicity tests real potential of innovative bio-products based on hot water extract of black spruce bark and of its fractions natural health products, antioxidants food supplements pharmaceuticals Ingredients of novel cosmetic products.

15 Sustainable production of laminated wood panels by rotational dowel welding ECO-CONCEPTION OF LAMINATED WOOD PANELS

16 Rotational wood-dowel welding produces wood joints of considerable strength without any adhesive, an opportunity to increase productivity reduce costs of the furniture production eliminate need for synthetic adhesives of petrochemical origin significantly reduce (eliminate) the time required for the gluing process

17 Sustainable chemistry and engineering principles involved in wood welding Use of Renewable Feedstocks Maximize Efficiency: maximize mass, energy, space, and time efficiency Minimize Material Diversity Material diversity in multicomponent products should be minimized to promote disassembly and value retention

18 Sugar maple (Acer saccharum) and Yellow birch (Betula alleghaniensis) investigated parameters : grain orientation, rotational speed and insertion speed on specially designed welding machine in CRIQ Temperature profile measurements at the interface -the maximum temperature applied in the study of the gases which are released in form of fume during wood welding. Optimal welding parameters based on mechanical properties of the welded products determined from the dowel withdrawal

19 Optimal welding parameters - machine designed for the project rotational speed of 1000 RPM for both species A 25 mm s -1 insertion speed for sugar maple 16.7 mm s -1 insertion speed for yellow birch Peak welding temperatures with optimal parameters: 244 C for sugar maple and 282 C for yellow birch To prepare panel specimens, 25x30x225 mm slats of sugar maple and yellow birch wood were cut from clear wood material.

20 Scheme of a dowel-welded panel

21 Rotational dowel-welding dowels : 9.68 mm in diameter and 96 mm welded by insertion into pre-drilled holes (7.67 mm in diameter and 50 mm deep into two adjacent slats as illustrated Same species for each dowel slat combination Friction between the dowel and substrate during insertion (less than 3 s) combined with high-speed dowel rotation: temperature rise, thermochemical transformations of lignin and carbohydrates, molten material which upon the release of pressure solidifies and ultimately induces the wood to weld

22 Advantages of rotational wood dowelwelding The usual adhesive in hardwood panelling polyvinyl acetate (PVA), requires long curing time (up to 24 hours) and multiple handling These constraints limit the production flow and flexibility required for customized production Dowel wood welding improves the efficiency of production, reduces the use of petrochemicals, lowering of production costs

23 Adhesion mechanisms in wood-to-wood welding Material collected from the welding zone analysed by Py-GC-MS, XPS and FT-IR The results obtained reveal that the thermochemical changes can be related to the mechanisms involved in fast pyrolysis, characterized by high pressures applied which are limiting the availability of the oxygen at the interface.

24 Study of gases released during wood welding VOCs studied by Pyr-GC-MS no harmful gases valuable information for air safety inspections important for future implementation of wood-welding technology The composition of the non-condensable gases (NCG) was close to that found in pure air, CO was not detected, traces of CO 2 and hydrogen The wood-welding technology developed by our team with a specially designed machine by CRIQ can be applied to the eco-conception of wood-welded panels for furniture and other indoor appearance applications

25 Small-scale crib 100% sugar maple No adhesive 66 cm wide (26 ) 46 cm high (18 ) 36 cm deep (14¼ ) 228 wood dowels

26 Potential of wood welding technology in green construction Our preliminary results with dowel-welding of black spruce indicate a potential of applying this technology in green (sustainable) construction Same line with the results published on manual dowel welding of Norway spruce (Bocquet et al., 2007 a,b).

27 Conclusions Black spruce bark extract with hot water contributes to saving atoms in molecules recovered by extraction with green solvent Extracted bark remains available as source of fibres or energy Wood welding -assembling wood slats into laminated panels relies on wood chemistry and implicates several sustainable chemistry and engineering principles ecological panels fully recyclable at the end of service life The public awareness of environmental and health implications of wood transformation -a shift towards sustainable wood transformation based on principles of green chemistry and sustainable engineering.

28 Acknowledgments and partners 55th International Convention of Society of Wood Science and Technology, Beijing, 27-31

29 Acknowledgments to project participants Martha Estrella Garcia Perez, Ph.D student Benoit Belleville, Ph.D student Gina Rodriguez, M.Sci student Ying Sun, M.Sci student Papa Niokhor Diouf, postdoctoral fellow Mariana Royer, postdoctoral fellow Maria Prado, M. Sci student Sanja Erakovic, Ph.D student