CHARACTERIZATION OF MODIFIED WOOD IN RELATION TO …cost-fp1006.fh-salzburg.ac.at/fileadmin/documents/... · ash wood with EPI adhesives Krystofiak Tomasz, Lis Barbara, Muszyńska

CHARACTERIZATION OF MODIFIED WOOD IN RELATION TO WOOD BONDING AND

COATING PERFORMANCE Workshop Proceedings

Edited by Dr. Sergej Medved & Dr. Andreja Kutnar

COST Action FP0904 “Thermo–Hydro–Mechanical Wood Behaviour and Processing”

and

COST Action FP1006 “Bringing new functions to wood through surface modification”

Department of Wood Science and Technology

Biotechnical Faculty, University of Ljubljana

and

University of Primorska, Andrej Marušič Institute

Rogla, Slovenia, October 16th to 18th, 2013

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©Sergej Medved, Andreja Kutnar

Proceedings of the COST FP0904 & FP1006 International Workshop on Characterization of

modified wood in relation to wood bonding and coating performance, Rogla, Slovenia,

October 16th to 18th 2013

Editor: Sergej Medved, Andreja Kutnar

Publisher: University of Ljubljana, Biotechnical Faculty, Department of Wood

Science and Technology, Rožna dolina, Cesta VIII/34, 1000 Ljubljana,

Slovenia. Phone: +386 1 320 30 00, Fax: +386 1 257 22 97

University of Primorska, Andrej Marušič Institute, Muzejski trg 2, 6000

Koper, Slovenija. Phone +386 5 611 75 00, Fax: +386 5 611 75 30

Edition: 100 copies

Ljubljana, 2013

CIP – Kataložni zapis o publikaciji Narodna in univerzitetna knjižnjica, Ljubljana 674.028.9(082) 630*82(082) COST Action FP0904 Thermo-‐Hydro-‐Mechanical Wood Behaviour and Processing (2013 ; Rogla) Characterization of modified wood in relation to wood bonding and coating performance : workshop proceedings / COST Action FP0904 Thermo-‐Hydro-‐Mechanical Wood Behaviour and Processing and COST Action FP1006 Bringing New Functions to Wood through Surface Modification, Rogla, Slovenia, October 16th to 18th, 2013 ; edited by Sergej Medved & Andreja Kutnar ; [organizers] Department of Wood Science and Technology, Biotechnical Faculty, University of Ljubljana and University of Primorska, Andrej Marušič Institute. -‐ Ljubljana : Biotechnical Faculty, Department of Wood Science and Technology ; Koper : University of Primorska, Andrej Marušič Institute, 2013 ISBN 978-‐961-‐6144-‐37-‐7 (Biotechnical Faculty, Department of Wood Science and Technology) 1. Gl. stv. nasl. 2. Medved, Sergej 3. COST Action FP1006 Bringing New Functions to Wood through Surface Modification (2013 ; Rogla) 4. Biotehniška fakulteta (Ljubljana). Oddelek za lesarstvo 5. Univerza na Primorskem (Koper). Inštitut Andrej Marušič 269303808

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The opinions expressed in the presented papers are those of the authors and do not

necessarily represents those of the editor.

All rights reserved. No parts of these Proceedings may be reproduced or transmitted in

any form or by any means, including photocopy, recording, or any information storage

and retrieval system, without permission in writing from publisher.

Technical editor: Sergej Medved

Printed by: Somaru, d.o.o. Rožna dolina, Cesta XV/26, 1000 Ljubljana, Slovenia

I

PREFACE

About COST Action FP0904

The polymeric components of wood and its porous structure allow its properties to be

modified under the combined effects of temperature, moisture and mechanical action –

so-‐called Thermo-‐Hydro-‐Mechanical (THM) treatments. Various types of processing

techniques, including high temperature steam with or without an applied mechanical

force, can be utilized to enhance wood properties, to produce eco-‐friendly new materials

and to develop new products. During these THM treatments, wood undergoes mechano-‐

chemical transformations, which depend upon the processing parameters and material

properties. An investigation of these phenomena requires collaboration between groups

from different wood disciplines; however, to date research has been rather fragmented.

This COST Action aims to apply promising techniques in the fields of wood mechanics,

wood chemistry and material sciences through an interdisciplinary approach to improve

knowledge about the chemical degradation and mechanical behavior of wood during

THM processing. This will help overcome the challenges being faced in scaling-‐up

research findings, as well to improving full industrial production, process improvement

and the enhancement of product properties and the development of new products.

About COST Action FP1006

Many applications of products are determined by their special surface properties, and

based on the physical, chemical and biological interchange of various molecules with the

materials surface. This is especially true for the use of wood and wood based products

due to the special wood characteristics like anisotropy, UV-‐degradation. Thus, bringing

new functions to wood through surface modification is needed in order to enhance the

quality of the existing wood products and to open the way to new applications, products

or markets.

This COST Action aims to provide the scientific-‐based framework and knowledge required

for enhanced surface modification of wood and wood based products towards higher

functionalization and towards fulfillment of higher technical, economic and

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environmental standards. This will be achieved by working within three main areas: Wood

surface modification and functionalization, Wood interface modification and interface

interaction and Process and Service life modelling.

The aim of this event is to present materials, technologies, and characterization

techniques in relation to wood bonding and coating performance of modified wood:

• Modification techniques (new and/or improved)

• Characterization of modified wood surface

• Formation and properties of the bond line/coating system

• Performance of coated modified wood

• Performance of bonded modified wood

• Performance of surface wood – based panels made from/or in combination with

modified wood

The Workshop has been organized by the Department of Wood Science and Technology,

Biotechnical Faculty, University of Ljubljana and Andrej Marušič Institute, University of

Primorska. Support and help was also provided by the Scientific Committee, reviewers

and by the COST FP0904 and FP1006 Management Committee. The organisers and the

editors would like to thank to all that help at organizing this Workshop, reviewers,

speakers and also session moderators.

We hope that you enjoyed the Workshop and that you will find these papers useful in

your future work.

Sergej Medved

Andreja Kutnar

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ORGANISING SCIENTIFIC COMMITTEE AND REVIEWERS

Stefanie Wieland (FP1006 Chair)

Parviz Navi (FP0904 Chair)

Lone Ross Gobakken (FP1006 Vice Chair)

Dennis Jones (FP0904 Vice Chair)

Mark Hughes (FP0904 WG1 Leader)

Lennert Salmen (FP0904 WG2 Leader)

Peer Haller (FP0904 WG3 Leader)

Gerhard Gruell (FP1006 WG1 Leader)

Holger Militz (FP1006 WG1 Vice-‐Leader)

Electra Papadopoulou (FP1006 WG2 Leader)

Graham Ormondroyd (FP1006 WG2 Vice-‐Leader)

Sergej Medved (FP1006 WG3 Leader)

Jakub Sandak (FP1006 WG3 Vice-‐Leader)

Andreja Kutnar (FP0904 member)

IV

TABLE OF CONTENTS

THM – a Technology Platform or Novelty Product? Frederick A. Kamke ........................................................................................................... 8

Characterization of laser modified wood surfaces for resin-‐free adhesion Scott Renneckar, W. Travis Church, Jeffrey Dolan, Zhiyuan Lin, Charles E. Frazier ........ 16

Emissions of thermally modified timber products Lothar Clauder, Maria Rådemar, Lars Rosell, Marcus Vestergren, Alexander Pfriem .... 23

Application of FT-‐NIR for recognition of substances used for conservation of wooden parquets of 19th century manor houses located in South-‐Eastern Poland

Anna Rozanska, Anna Sandak ........................................................................................ 32

Gluability of thermally modified ash wood with EPI adhesives Krystofiak Tomasz, Lis Barbara, Muszyńska Monika, Sobota Karolina .......................... 43

Bondability of phenol formaldehyde modified beech wood glued with phenol resorcinol formaldehyde and polyvinyl acetate adhesives

Alireza Bastani, Holger Militz ......................................................................................... 52

Bonding properties of wood modified with various siloxanes and silanes Marcus Müller, Markus Hauptmann, Christian Hansmann ............................................ 61

Viscoelastic thermal compressed wood as a component in green building composites Milan Sernek, Aleš Ugovšek, Andreja Kutnar, Frederick A. Kamke ................................. 67

Effect of heat treatment of spruce on adhesive bond performance after soaking in water

Mirko Kariz, Manja Kitek Kuzman, Milan Sernek ........................................................... 74

Effect of treatment medium on the moisture uptake rate and colour change during natural weathering of heat treated wood

Miklós Bak, Róbert Németh, Diána Csordós, László Tolvaj ............................................ 80

The Effect of Surface Weathering on the Water Sorption Properties of Wood Callum Hill ...................................................................................................................... 87

Coated Surface Densified Wood: Water Vapour Absorption and Desorption and Related Dimensional Changes

Marko Petrič, Mark Hughes, Borut Kričej, Andreja Kutnar, Kristiina Laine, Sergej Medved, Matjaž Pavlič, Lauri Rautkari ........................................................................... 94

V

Water repellent efficiency of wood treated with copper–azole combined with silicone and paraffin emulsions

Hüseyin Sivrikaya, Ahmet Can ...................................................................................... 101

Wood moisture analysis under THM-‐conditions by employing scaling properties of room temperature moisture isotherms

Wim Willems ................................................................................................................ 116

A structural study of the white rot biodegraded lime wood coated with poly(hydroxy urethane acrylate)

Carmen-‐Mihaela Popescu, Maria-‐Cristina Popescu ..................................................... 123

Wax impregnation slows down photodegradation processes of wood Boštjan Lesar, Matjaž Pavlič, Marko Petrič, Miha Humar ............................................ 130

Weathering performance of coatings on acetylated, furfurylated and heat treated wood at two exposure sites in Europe

Laurence Podgorski, Gerhard Grüll, Michael Truskaller, Jean-‐Denis Lanvin, Véronique Georges, Susanne Bollmus ........................................................................................... 140

Surface performance of thermally modified wood during weathering Michael Altgen, Jukka Ala-‐Viikari, Antti Hukka, Timo Tetri, Holger Militz ................... 149

Surface qualification of weathered wood Jean Strautmann, Marion Noël, Thomas Volkmer ....................................................... 157

The Influence of the Sodium Carbonate Treatment of Narrow-‐leaved Ash on the Lap Shear Strength

Jasmina Popović, Milanka Djiporović-‐Momčilović, Ivana Gavrilović-‐Grmuša, Mladjan Popović, Sergej Medved ............................................................................................... 167

Combined treatment using boron impregnation and thermo-‐modification to improve properties of heat treated wood -‐ Effects of additives on boron leachability

Solafa Salman, Anélie Petrissans, Marie France Thevenon, Stéphane Dumarcay, Benoît Pollier, Philippe Gerardin .............................................................................................. 175

Superb wood surface finishing – SWORFISH project approach Jakub Sandak, Anna Sandak, Mariapaola Riggio, Ilaria Santoni .................................. 191

Contact angle measurement as a method for quantitative analysis of wettability of plasma treated thermal modified timber

Judith Sinic, Uwe Müller ............................................................................................... 198

Spectral study of hydro-‐thermal treated lime wood Maria-‐Cristina Popescu, Carmen-‐Mihaela Popescu ..................................................... 206

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The comparison of fungal and bacterial laccase ability to oxidise different lignin model compounds and isolated lignins from lignocellulosic fibres

Helena Krajnc, Vanja Kokol .......................................................................................... 213

Exploratory Thermal-‐Hydro-‐Mechanical Modification (THM) of Moso Bamboo (Phyllostachys pubescens Mazel)

K.E. Semple, F.A. Kamke, A. Kutnar, G.D. Smith ........................................................... 220

The sorption properties of some thermally treated hardwoods analysed by thermodynamics, surface fractality and FT-‐NIR spectroscopy

Aleš Straže, Željko Gorišek, Stjepan Pervan, Anna Sandak, Jakub Sandak ................... 228

Modification of wood acoustic, hygroscopic and colorimetric properties due to thermally accelerated ageing

Elham Karami, Miyuki Matsuo, Iris Bremaud, Sandrine Bardet, Julien Froidevaux, Joseph Gril .................................................................................................................... 238

Changes in technological properties of thermally treated Gympie messmate wood Pedro Henrique Gonzalez de Cademartori, Patrícia Soares Bilhalva dos Santos, Darci Alberto Gatto, Jalel Labidi ............................................................................................ 246

Changes in chemical composition occurring in wood during the hydrothermal treatment process

René Herrera, Xabier Erdocia, Jalel Labidi .................................................................... 254

Colour changes in coated hydrothermally modified wood after artificial and outdoor exposure

Sansonetti E., Cirule D., Grinins J., Andersone I., Andersons B., ................................... 261

Characterization of wood surface degradation using activation spectra approach Vjekoslav Živković, Martin Arnold, Klaus Richter, Hrvoje Turkulin ............................... 268

Advantage of vacuum versus nitrogen to achieve inert atmosphere during wood thermal modification

K. Candelier, S. Dumarçay, A. Pétrissans, P. Gérardin, M. Pétrissans ........................... 279

A Rapid Method for Assessing Check Development in Veneer Overlays Michael Burnard, Lech Muszyński, Scott Leavengood, Lisa Ganio ............................... 287

The grindability of heat treated biomass: effect of treatment intensity on the production of particles suitable for the 2nd generation of BtL chain

F. Pierre, P. Lu, G. Almeida, P. Perre ............................................................................. 296

Stresses in the plans of bond lines in reconstituted solid wood under moisture variation: a numerical approach

Sung-‐Lam Nguyen, Rostand Moutou Pitti, Jean-‐François Destrebecq ......................... 303

VII

Heat flux study of mild pyrolyzed wood and components through microcalorimetry Pin Lv, Floran Pierre, Giana Almeida, Liang Li, Patrick Perré ........................................ 310

Analysis of the effects of the European oak natural variability on the modification of the density distribution and chemical composition during the heat treatment

Joël Hamada, Anélie Petrissans, Frédéric Mothe, Mathieu Petrissans, Philippe Gerardin ..................................................................................................................................... 317

Joint COST FP0904 & FP1006 International Workshop in Slovenia on Characterization of modified wood in relation to wood bonding and coating performance

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Keynote paper/presentation

THM – a Technology Platform or Novelty Product?

Frederick A. Kamke

Dept. Wood Science & Engineering, Oregon State University, Corvallis, Oregon USA

97331, [email protected]

ABSTRACT

Thermal-‐Hydro-‐Mechanical (THM) processing is an old idea that has arisen with a new

life. THM wood has impressive mechanical and physical properties, but this exciting

technology has some serious challenges for commercialization. This paper defines the

concept and scope of THM technology and provides some examples of commercial

application. Recent research in Europe, Asia, and North America has clearly demonstrated

that THM processing of wood improves strength, stiffness, hardness, and moisture

resistance; and this implies that the value of wood is also enhanced. The broad array of

process parameters and unique conditions clearly differentiates THM as a technology

platform. However, THM adds cost to processing and reduces wood volume. THM wood,

depending on the specific process conditions, may have large potential for swelling when

exposed to water. Technical challenges and process cost may limit THM processing to

novelty products. Clever scientists and engineers can address most of the technical

disadvantages of THM processing. However, the challenge for an entrepreneur, who has

visions for commercialization, is to create THM value that exceeds THM cost.

Keywords: wood modification, compression, densification, thermo-‐hydro-‐mechanical.

1 INTRODUCTION

Thermo-‐Hydro-‐Mechanical (THM) processing is an old idea that has been given new life

via research efforts around the world. It’s a very interesting concept – take some wood,

soften it with heat and steam, compress, and viola!, the result is a high density material


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with improved strength, stiffness, and hardness. The process is simple, it requires no

chemicals, and the properties of the wood are dramatically improved. So why hasn’t THM

processing been readily adopted? This paper will provide some historical background,

discuss challenges of commercialization, and present some personal observations.

1.1 BRIEF THM HISTORY

THM processing implies the strategic application of high temperature, moisture, and

mechanical compression toward the goal of reducing the void space in wood, and thus

increasing density. Prior to 1960, researchers and practitioners quickly recognized that

temperatures above 100°C, along with some moisture, sufficiently softens wood such that

it may be compressed without catastrophic failure. The moisture content was usually not

controlled during the densification process, and microscopic fractures in the cell wall

were often ignored. Compression was performed in hydraulic pressing systems that were

open to atmospheric conditions (open systems). Many wood densification equipment

designs and processing conditions were reported. While the details of why this process

worked were perhaps not clearly understood, the efforts produced wood products with

interesting characteristics. For the purpose of the present discussion, the use of high

temperature and mechanical compression, in the presence of significant moisture, and

with the intent to increase density, will be called THM processing.

Previous reviews of THM wood, also called “compressed wood” or “densified wood”,

reveal that a significant amount of research and some commercialization has occurred in

Europe and the United States (Kollman 1936, Morsing 2000, Sandberg et al. 2012) prior to

1960. Kollman (1936) described the state-‐of-‐the-‐art for compressed wood, and even

mentioned some investigations in Germany in the late 19th century. Seborg and Stamm

(1941) reported results from some early investigations of compressed wood that was

performed at the U.S. Forest Products Laboratory in Madison, Wisconsin. Readers are

referred to these previous reviews for more information about early THM processing.

Research in the U.S. led to very limited commercial application. In 1943 the Formica

Insulation Company (Cincinnati, Ohio) marketed Pregwood, which was a phenol-‐


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formaldehyde impregnated, laminated, veneer product that was processed with 50%

degree of compression. Pregwood was designed for the hub of aircraft propeller blades

with length up to 5m (Weick 1939). Pregwood was produced from parallel-‐laminated

maple veneer, with density of 1300 kg/m3, MOE of 24 GPa, and MOR of 330 MPa. Resin

impregnation was needed to overcome the greatest technical challenge for THM wood,

namely moisture-‐induced dimensional instability. Other early applications of THM wood

for commercial products were bobbins, picker sticks, and shuttles used in the textile

industry; as well as machine dyes, antenna masts and knife handles. Most of these

products were resin-‐impregnated (presumed for dimensional stabilization).

Since 1990 there has been renewed interest in developing THM products. Research in

Japan explored surface densification of lumber (Inoue et al. 1990), shape-‐forming of

round wood into prismatic shapes (Ito et al. 1998), and fixation of set recovery by hydro-‐

thermal and chemical treatment (Inoue et al. 1993a, Inoue et al. 1993b). In Europe, one

critical area of focus was the problem of shape recovery upon exposure to water (Navi et

al. 1997, Tomme et al. 1998). For more details refer to Sandberg et al. (2012). The current

COST Action FP0904 is further evidence of renewed research interest in THM processing,

however, commercial application is still very limited.

1.2 COMMERCIAL PRODUCTS

Solid THM wood products are rare to find on the commercial market. Calignum

(Gothenburg, Sweden), who developed a densified solid wood via an isostatic membrane

press, liquidated its assets in 2012. The Calignum technology was acquired by the Tarkett

Company (Nanterre Cedex, France), who also announced their intension to produce a

densified eucalyptus flooring product in 2011. Apparently, this has not occurred. There

are some commercial operations in Japan. However, information has been difficult to

obtain. MyWood2 Corporation (Iwakura, Aichi, Japan) manufactures densified solid cedar

wood products. Their primary market is flooring in Japan and China, and products are sold

for use in furniture. The MyWood2 product is impregnated with a proprietary polymer to

provide resistance to water, and compression is approximately 50 percent.


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Electric transmission support components made from THM wood are typically resin-‐

impregnated, laminated veneer. Low molecular weight resins (typically phenol-‐

formaldehyde) are used to impregnate veneer, which is then partially cured in an oven. A

billet is then formed from the laminas, with orientation of the veneer dependent on the

intended application. The billets are compressed in a heated press (open system) to

density of approximately 1300 kg/m3. This line of products is desired for high electrical

resistivity, high dimensional stability, and high strength to weight ratio. Another

application or resin-‐impregnated veneer THM is liquid natural gas (LNG) storage

containers and associated support structures. A laminated design permits components

with wide dimensions that could not be achieved with THM lumber. For this application,

low thermal conductivity, high dimensional stability, and high strength to weight ratio are

important. Other applications for resin-‐impregnated veneer THM include wear plates for

machinery and transportation vehicles, machine pattern molds, bulletproof barriers, and

some structural building components. There are several products in this market,

including, but not limited to, Insulam® by CK-‐Composites (Mount Pleasant, Pennsylvania

USA), Lignostone® by Röchling (Harren, Gemany) and Lignostone® (Ter Apel,

Netherlands), dehonit® by Deutsche Holzveredelung Schmeing GmbH & Co. KG

(Kirchhundem/Würdinghausen, Germany), and Ranprex® by Rancan Srl (Vincenza, Italy).

The PureTimber company (Gig Harbor, Washington USA) produces a cold bendable wood

product that was patented by the Danish Technical Institute (Hansen et al. 1993). Other

companies have licensed the technology (e.g. Compwood Products, Hungary). The

method employs THM techniques to compress wood elements (approx. 2.5 m) in the

longitudinal direction. Length is reduced approximately 20% in process, but recovers to

approximately 90% of original dimension when complete. The wood moisture content

must be above 25%. Side restraint prevents buckling, however, the cell walls buckle, and

partial shear failure between adjacent cell wall layers probably occurs. While the wood is

still wet, it may be bent in one or two axes with little mechanical force. Once dried, the

wood is no longer bendable. Applications include architectural woodwork, furniture,


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musical instruments, and boat hulls. Retail cost is approximately $19,000/m3, so this is an

example of very high value and low production volume THM wood.

2 CHALLENGES FOR COMMERCIALIZATION

The greatest challenges for expanded commercialization of THM technology are: 1) scale-‐

up from laboratory processes, 2) loss of volume yield, 3) swelling potential, and 4)

profitability. All of these challenges are related in some way, and any one of them may be

overcome with clever engineering or the right product application.

The challenge of scale depends on the industrial application. If the application is high

value, a simple batch process, with moderate capital investment, may be adequate. One

must also consider the physics of heat and mass transfer, as well as the compression

forces required for a large THM device. The time required for a specific temperature or

moisture content change via unsteady-‐state heat and mass transfer is approximately

proportional to the second power of the principal thickness of the material being

processed. If one doubles the thickness, the processing time required to achieve the

desired change in temperature or moisture content increases by a factor of four. For

example, a THM process step that requires 10 minutes in a small laboratory device may

require 100 minutes to produce a larger commercial product. The impact on production

capacity is devastating. Compression force (e.g. N, not N/mm2) on a small laboratory test

sample increases in proportion to the area normal to the direction of applied force.

Consequently, hydraulic pumps and press frames in a commercial THM device must be

sized accordingly, with significant impact on capital investment.

Most wood processing companies closely monitor the volume of wood that enters the

factory and the volume of production that leaves the factory. Productivity is often

expressed as percentage of volume yield. Most THM technologies dramatically reduce

volume, perhaps by 50% or more. Traditional wood processing mentality resists any

change that reduces volumetric productivity, even if the process is profitable.

The moisture-‐induced swelling potential of wood is proportional to its density. Swelling of

untreated wood is reversible, but most swelling of THM wood is not reversible. Additional


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process steps may be used to reduce THM swelling, such as hydro-‐thermal treatment or

some chemical treatment. However, additional treatment adds cost to the final product,

and may cause undesirable characteristics, such as darker color and embrittlement.

Processing cost is not the critical factor for THM wood. Profitability determines

commercial success. All of the technical challenges may be overcome, and indeed have

been achieved as demonstrated by numerous research reports. If the value of the final

product significantly exceeds the cost of production, then the commercial enterprise will

be viable. As researchers, we provide technical solutions to problems. However,

sometimes we must define the problem within the limitations of commercial reality.

3 PROPOSED APPLICATIONS AND OBSERVATIONS

THM processing is a technology platform. There are several process parameters that may

be manipulated to create intermediate or final products with a broad range of

application. With a robust menu of products, a manufacturer may readily adapt to

changing markets and price volatility. The long-‐term success of the manufacturers of

resin-‐impregnated veneer THM products is due to the many high value product

applications. The same capital equipment is used to produce products for the tool and

dye industry, electrical power distribution, and cryogenic fluid storage and transport

industries. The manufacturer manipulates density, resin content, and veneer orientation

to effectively support each of these industries. Solid THM wood flooring is the target

market for MyWood2 and Tarkett. I believe an engineered composite would be more cost

effective and a more efficient use of raw materials in flooring applications. My own

research has examined the use of THM wood veneer in laminated veneer lumber (LVL) for

building construction. Profitability for commodity building products depends on low cost.

THM-‐LVL has been demonstrated to have superior mechanical properties than

conventional LVL, but processing cost is higher. Therefore, THM-‐LVL can’t compete

against current LVL products. Either higher value LVL applications are needed or raw

material cost must be lower. The key to commercial success is to establish a technology


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platform, where one facility has the capability to manufacture a broad range of THM

products as the market evolves.

4 REFERENCES

Hansen O., Ljorring J., Thomassen T. 1993. Method and apparatus for compressing a

wood sample, US Patent No. 5190088A.

Inoue, M., Norimoto, M., Otsuka, Y., Yamada, T. 1990. Surface compression of coniferous

lumber, I. A new technique to compress the surface layer. Mok. Gak. 36(11):969-‐975.

Inoue, M., Norimoto, M., Tanahashi, M. 1993a. Steam or heat stabilization of compressed

wood. Wood and Fiber Sci. 25(3): 224-‐235.

Inoue, M., Norimoto, M., Tanahashi, M., Rowell, M. 1993b. Steam or heat fixation of

compressed wood. Wood and Fiber Sci., 25(3), 224-‐235.

Inoue, M., Norimoto, M., Tanahashi, M., Rowell, M. 1993c. Fixation of compressed wood

using melamine-‐formaldehyde resin. Wood and Fiber Sci. 25 (4): 404-‐410.

Ito, Y., Tanahashi, M., Shigematsu, M., Shinoda, Y. and Otha, C. 1998. Compressive-‐

molding of wood by high-‐pressure steam-‐treatment: Part 1. Development of

compressively molded squares from thinnings. Holzforschung 52: 211-‐216.

Kollmann, F. 1936. Technologie des Holzes. Springer-‐Verlag, Berlin.

Morsing, N. 2000. Densification of wood: The influence of hygrothermal treatment on

compression of beech perpendicular to the grain. Dept. Structural Engineering and

Materials, Technical University of Denmark, Series R, No. 79., Lyngby, Denmark.

Navi, P., Huguenin, P., Girardet, F. 1997. Development of synthetic-‐free plastified wood

by thermohygromechanical treatment. In: Proc. The Use of Recycled Wood and Paper

in Building Applications. For. Prod. Soc. Proc. No. 7286, Madison, Wisc. P. 168-‐171.

Seborg, R.M., Stamm, A.J. 1941. The compression of wood. US For. Prod. Lab. Rep. No.

R1258, Madison, Wisc. USA.


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Tomme, F-‐P., Girardet, F., Gfeller, B., Navi, P. 1998. Densified wood: an innovative

product with highly enhanced characteristics. In: Proc. World Conf. on Timber

Engineering, Eds. Natterer, J., Sandoz, J-‐L., Swiss Fed. Inst. Tech., August 17-‐20, 1998.


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Keynote paper/presentation

Characterization of laser modified wood surfaces for resin-

free adhesion

Scott Renneckar1, W. Travis Church2, Jeffrey Dolan1, Zhiyuan Lin1, Charles E. Frazier1

1 Department of Sustainable Biomaterials, 230 Cheatham Hall, Virginia Tech, Blacksburg,

VA 24060, USA, [email protected]

2 5919 New Albany Rd W, New Albany, OH 43054, USA

ABSTRACT

Laser irradiation of wood is a new method of bonding two wood substrates. Irradiating

the surface of wood with laser light, within an optimal set of parameters, causes the

wood surface to change and subsequently undergo bonding when hot-‐pressed. Light

microscopy and scanning electron microscopy were utilized for surface topology analysis.

Dependent upon the amount of energy density, laser modification created a grooved

surface or a flat surface. Chemical analysis of the residue after laser-‐modification was

conducted and the polysaccharide and Klason lignin content of the extracted products

were evaluated using ion chromatography. Additionally, chemical analysis of the wood

surface was performed using FTIR spectroscopy. The surface of wood after laser light

exposure was decorated with a “glass-‐like” layer, which consists of modified lignin with

some polysaccharide degradation products, and evidence of cellulose melting.

Subsequently, wood samples with modified surfaces were hot-‐pressed together creating

a wood composite. Screening of multiple factors that would contribute to surface

modification and adhesion was performed utilizing mechanical testing. Laser light

modified wood composites were tested in shear for mechanical strength, using a design

of an experiment (DOE) approach to optimize hot-‐pressing parameters. It was found via

initial screening and DOE experiments that laser power density as well as and hot press

pressure were significant factors to optimize bonding. Laser-‐modified 3-‐ply veneer


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samples had values that were comparable to control samples created using phenol

formaldehyde resins. The data suggests that laser-‐activated bonding of wood can yield a

wood composite requiring no liquid adhesives as the wood itself serves the dual role of

adhesive and substrate.

Keywords: CO2 laser, wood surface chemistry, plywood, auto-‐adhesion

1 INTRODUCTION

Wood surfaces are complex arising from the destruction of the cell wall material,

migration of water and extractive components to the surface, and the contamination of

the surface with dust and other air-‐borne materials. Additionally, heat is generated at the

surface during cutting operations and subsequent elevated temperatures during drying

can alter the type and quantity of functional groups at the surface (Sernek et al. 2005).

Moreover, wood surfaces can be purposefully modified through exposure to different

forms of energy. One of the oldest and classic examples is the flame treatment of wood

for storage of food and drink. Due to the high quantity of energy transferred, in a short

period of time, lasers are able to modify wood differently than other modification

methods with slower heat rates. Laser light interaction with wood results in charring,

ablation, and melting, depending on a multitude of variables that are related to wood

properties and laser parameters. Laser light affects the irradiated area and the resulting

laser modification is described in 3 levels, which are cumulatively known as the heat

affected zone, or HAZ. This zone can be up to 100 microns thick, depending on wood

variables, laser variables, and their interaction. Parameswaran (1982) described the first

level as a black, smooth laser cut surface that is approximately 25 microns thick. Softening

and melting as a result of laser light and wood interaction suggests the process is such

that kinetics of softening and melting can surpass the kinetics of thermal degradation

(Schroeter and Felix 2005).

Past research indicated that the laser modification of wood affects the lignin and

hemicellulose components to the greatest extent, while effecting cellulose to a lesser

degree (Kubovsky 2009). It was found that laser modification primarily caused


18

degradation of hemicellulose and lignin (Kubovsky 2009). Specifically the hemicellulose

underwent deacetylation, while bond cleavage occurred in lignin, specifically the aryl-‐

alkyl ether bonds in lignin were broken. This bond cleavage induced further condensation

reactions. Other research indicated that the modification of components was preferential

towards reducing the methoxy side groups of lignin (Walinder et al. 2009). Additional

studies have investigated laser modification specific to cellulose. The studies were based

on the concept of applying enough energy, induced by a combination of frictional heat

and via laser, in order to chemically and/or physically change viscose grade wood pulp,

which is noted to have a high α-‐cellulose content, into clear films. A calculation was made

for the amount of energy required to “weaken and unlock” the intermolecular hydrogen

bonds in cellulose. It was found that this energy would need to be 20kJ/mol, or 3.3*10-‐20 J

per bond, which is equivalent to 1 photon with a wavelength of 6 microns (Schroeter and

Felix 2005). Although the IR spectra indicated little change, qualitatively it was evident

that the material changed from a fibrous opaque structure to a transparent smooth

structure. With these results the researchers concluded they were able to melt cellulose.

Previous researchers have observed the “melting” of lignocellulosic materials with laser

modification, some suggesting lasers melting only related to a specific component, with

other suggesting that all wood components can undergo thermal softening and melting.

In the current research, we examine the surface of laser modified wood with a variety of

chemical analysis techniques to understand chemical changes induced by the laser

modification as well as investigate the parameters that lead to strong bondlines when

two laser modified surfaces are hot pressed together.

2 MATERIALS AND METHODS

2.1 MATERIALS

3.2 mm thick “Grade A” Yellow-‐poplar (Liriodendron tulipifera) and southern yellow pine

(Pinus spp.) rotary-‐peeled veneer were obtained from a southeastern US laminated

veneer mill. The as-‐received 60x60cm samples were conditioned to 12% moisture content

in a walk-‐in environmental humidity controlled room.


19

2.2 METHODS

Wood veneer samples were modified utilizing a ULS-‐V460 60W carbon dioxide laser with

high power density focusing optics, resulting a circular spot size with a minimum diameter

of approximately 50 μm. Laser wattages of 3 to 60W were utilized, with the laser moving

at a speed of 0.1 m/s to 0.5 m/s, at 40,000 pulses per meter. Specific parameters utilized

in the ULS print driver included a maximum image density of 6, tuning of zero, while

utilizing vector mode. The trajectory of the laser was designed in AutoCAD, using the

smallest resolution usable by the laser between lines, 0.002 in (50.4 μm) to irradiate the

surface. Laser modified samples were placed in contact matching their irradiated surfaces

and subsequently hot pressed together utilizing a MP2000 mini hot press at 200 °C (Fig.

1). The time between laser modification and hot pressing ranged from 5 min to weeks;

with no detectable difference in bond strength. Pulse Amperometric Detection Ionic

chromatography (IC) was used for sugar analysis of the laser modified poplar versus

remaining bulk wood.

Figure 1: Process segments for laser modified wood bonding; (left) Autocad file for read/write laser

modification of wood surface, (center) laser modification of southern yellow pine veneer,

(right) hotpress system used to make test specimens.

3 RESULTS AND DISCUSSION

In Fig. 2, a 3-‐D light microscopy image indicates a distinct difference of the laser-‐modified

wood surface. The samples appear to have a glossy, reflective surface with dark spots

that speckle the surface. The sides of the sample reveal that laser modification is limited

to the surface of the sample. For softwoods, measurements of the heat affected zones


20

show earlywood tracheids are modified on average of 19.7 micrometers in depth, while

latewood tracheids are modified on average of 8.1 micrometers. Fiber tracheids and ray

parenchyma have approximately 11 micrometers of modification. Others have reported

that the density variations in the wood greatly impact depth of treatment, as cell wall

thickness directly impacts the laser ablation process.

Figure 2: 3-‐D light microscopy image of laser modified yellow-‐poplar.

The spacing of the line and the focus of the laser spot size were controlled to manipulate

surface geometries from a flat surface to a highly grooved surface. As the in-‐focus laser

spot size was smaller than the resolution of the laser's motion system, ridges develop

between laser lines during laser modification (Figure 3a). In addition the Gaussian shape

of the power of the laser beam creates a spot size with additional energy in the center.

As mechanical interlock of ridges may promote adhesion, the presence of the ridges was

thought to have a substantial positive effect on the bonding (Fig. 3b). However, for laser

bonding to occur, mechanical interlock “micro-‐finger joints”, was not required (Fig. 3c,d).

Surprisingly, smooth surfaces showed higher compressive shear strengths than the

grooved samples (6.2 MPa vs. 3.5 MPa, respectively). Highest shear strengths were found

for samples with the most pressure during bonding (2 MPa). This data suggests that the

laser-‐modified surfaces are limited by their inability to bridge differences in surface

roughness. When appropriate conditions were used for bonding, 3-‐ply specimens had a

bending modulus between 7 and 10 GPa and bending strength 60 to 80 MPa.


21

Figure 3: (a) SEM image of laser modified wood with high concentrated energy causing grooves in

surface; (b) image of bondline of two specimens from (a); (c) SEM image of laser modified

wood with low concentrated energy resulting in relative flat surface topography; and (d)

image of bondline of two specimens from (b)

Surface material of laser treated wood was isolated through extraction. A number of

solvents were evaluated for their ability to refresh the surface, removing all residues from

the surface. Solvents tested were the following: alcohols like methanol and ethanol;

acetone; selective lignin solvents like aqueous dioxane; dimethylsulfoxide (DMSO), 0.1 M

NaOH, and water. Dimethylsulfoxide was successful in removing the primary heat

affected zone of the surface. The DMSO extract was evaluated by precipitating the

polymeric materials with acidic ethanol, followed by a two-‐step acid hydrolysis for

composition analysis of these materials. This data provided the monomeric carbohydrate

component percentage related to the wood polysaccharides extracted as well as the

Klason lignin content. It was found that the cellulose content increased from 47.7 to

61.9% and the lignin content of the surface increased from 21.1 to 27.9%, and the xylan

content was greatly reduced to less than 4%. Analysis of the water extracted surface

material revealed a large amount of xylose, as well as monomeric degradation products

such as hydroxymethyl-‐furfural, levoglucosan, xylitol and sorbitol. While a number of

possible compounds were found to be present that could be reactive, no specific reactive

chemistry was detected suggesting bonding occurred because of intimate contact of

surfaces during hot-‐pressing.

a b

c d


22

4 CONCLUSIONS

CO2 laser modification of wood ablates the surface of wood leaving a residue on the

wood surface. Dependent upon the laser energy density, the surface topology changes

from a grooved surface to a relatively flat surface. The residue remaining on the wood

surface is composed of the native wood polymers and degradation products. This residue

alone provides adequate adhesion to form composite materials when two specimens are

bonded together under pressure and heat.

5 REFERENCES

Buschbeck L., Kehr E., Jensen U. 1961a. Untersuchungen über die Eignung verschiedener

Holzarten und Sortimente zur Herstellung von Spanplatten – 1. Mitteilung: Rotbuche

und Kiefer. Holztechnologie, 2, 2: 99–110

Kubovsky, I., 2009. FT-‐IR Study of Maple Wood Changes due to CO2 Laser Irradiation.

Cellulose Chemistry and Technology, 43(7-‐8): p. 235-‐40.

Parameswaran, N., 1982. Feinstrukturelle Veränderungen an durch laserstrahl getrennten

Schnittflächen von Holz und Holzwerkstoffen. European Journal of Wood and Wood

Products, 40(11): p. 421-‐428.

Schroeter, J. and F. Felix, 2005. Melting cellulose. Cellulose, 12(2): p. 159-‐165.

Sernek, M., Kamke, F.A. and Glasser, W.G., 2004. Comparative analysis of inactivated

wood surfaces. Holzforschung, 58:22-‐31

Walinder, M., et al., 2009.Micromorphological studies of modified wood using a surface

preparation technique based on ultraviolet laser ablation. Wood Material Science and

Engineering, 4(1): p. 46 -‐ 51.


23

Emissions of thermally modified timber products

Lothar Clauder1, Maria Rådemar2, Lars Rosell2, Marcus Vestergren2, Alexander Pfriem1

1 Eberswalde University for Sustainable Development, Friedrich-‐Ebert-‐Straße 28, 16225

Eberswalde, Germany, [email protected]

2 SP Technical Research Institute of Sweden, Box 857, SE-‐501 15 Borås, Sweden,

[email protected]

ABSTRACT

In this study the applicability of wood in the museum environment was investigated. The

applied method focused on an appropriate selection of materials and adequate control of

their noxious compounds as keys to achieve compatibility between display materials and

artworks. Therefore specimens of fresh-‐sawn Fir (Abies alba, Mill.) and Alder (Alnus

glutinosa, (L.) Gaertn.) were pre-‐treated with a buffer-‐solution and heat-‐treated at low

temperatures. The Field and Laboratory Emission Cell (FLEC) were applied for measuring

the volatile organic compounds (VOC) and the formaldehyde (FA) emissions from wood.

The emissions were characterised by using gas chromatography (GC) in combination with

mass-‐spectra (MS) and flame ionization detection (FID), ion chromatography (IC) and

high-‐performance liquid chromatography (HPLC). Compared to samples of green Fir, the

formaldehyde emissions increased in the kiln-‐dried samples. However these emissions

were decreased in the impregnated and thermally modified samples. Thermally treated

and dried variants of Alder samples showed low amounts of VOC, in particular due to

aldehydes (>C2). The low amount of acidity and decreased formaldehyde formation in the

Alder samples increased the positive trend. Concerning the detection limits for

substances with high contamination potential for individual display case construction

materials, this study gives a first hint on how the VOC emissions of thermally modified

timber could be minimized by using a buffer solution before the heat treatment.

Keywords: thermally modified timber, gas chromatography, high-‐performance liquid

chromatography, ion chromatography, volatile organic compounds.


24

1 INTRODUCTION

Wood emits volatile organic compounds (VOC). Thus, the applicability of wood in the

museum environment, e.g. as material for the construction of display cabinets, is almost

entirely restricted due to the required controlled climate and air purity, which is very

different from normal indoor air, e.g. in dwellings, offices, schools etc. The desire to

preserve exhibits, constituted by all imaginable materials, from deterioration allows in

principle only low levels of air pollutants with possible detrimental effects (Englund 2010).

The purpose of this study was to develop and test a suitable method to minimize the

emissions. Schäfer and Roffael (2000) proposed reaction mechanisms of FA formation

from wood and demonstrated an increase of FA emission at elevated temperatures and

prolonged heating times during panel production. Especially during the pressing step at

elevated temperatures increased FA and VOC emissions were detected in the absence of

any resin (Carlson et al. 1995). Even at temperatures below 100°C, as during the kiln

drying of the wood, the hydrolysis of cell wall components cellulose, polyose

(hemicellulose) and lignin leads to formation of furfural, formaldehyde and very volatile

acids (VVOC, e.g. formic acid). The approach was to reduce the emissions of thermally

modified timber products, based on impregnation with a sodium-‐boric-‐buffer-‐solution.

2 EXPERIMENTAL

Alder (Alnus glutinosa, (L.) Gaertn.), which is low emitting, and Fir (Abies alba, Mill.) were

selected. Sample preparation was performed at the Eberswalde University for Sustainable

Development. The fresh-‐sawn specimens (210×210×20 mm³) were taken out of two

stems, each approximately 60 years old, harvested in Northeast Germany. The

experimental test set-‐up consisted of 2 samples for each variant of treatment (Table 1).


25

Table 1: Experimental test set-‐up

Specimen [n] Treatment

2 untreated

2 kiln dried

2 modified

2 impregnated kiln dried

2 impregnated modified

3 METHODS

3.1 SET UP FOR pH VALUE MEASUREMENTS

In general, wood species range in pH from 3.0 to 5.5 (Stamm 1964). A pH range of 4.00 to

5.86 for hardwoods, e.g. 5.52 for Alder and 4.02 to 5.82 for softwoods, e.g. 4.02 for Fir

was found (Johns 1980). The impregnation with the buffer solution was performed in a

Pressure Impregnation plant. After impregnation, small samples were dissolved in

distilled water then pH-‐value measurements were carried out with a WTW pH meter,

Model inoLab by using an electrode to measure the extracts. To determine the potential

of the buffer solution with a pH-‐value of 9.4, the following equilibrium equation (Eq.1)

was used, e.g. to calculate the amount of protonated acetic acid molecules inside the pre-‐

treated wood.

pH = pKa + lg [b]/ [a] (Eq. 1)

[b] = base (e.g. sodium acetate); [a] = acid (e.g. acetic acid); pKa = negative logarithm of the equilibrium constant (e.g. acetic acid & sodium acetate)

3.2 SET UP FOR F IELD AND LABORATORY EMISSION CELL

A variety of test methods for determining FA emissions from wood and wood products

have evolved over time. As reference methods the American National Standards (ANSI),

e.g. for particleboard (A.208.1 2009), as the emission standards of the California Air

Resources Board (CARB 2008) and the chamber method according to DIN EN 717-‐1 (2004)

specify large chamber tests. The large chamber test is expensive, time consuming and

needs a large amount of samples. Therefore it is impractical for quality assurance in


26

commercial production (Birkeland et al. 2010). Due to reliable correlation to these

reference methods, derived and approved secondary methods, e.g. the perforator

method (EN 120 1993), gas analysis method (EN 717-‐2 1994) and desiccator-‐test, as

described in ASTM D 5582-‐00 (2006) have been established. For this reason in this study

the measurements of the emissions from wood were performed according to ISO 16000-‐

10 (2006) with a Field and Laboratory Emission Cell (FLEC), which provides a simulation of

realistic indoor air conditions with respect to temperature and relative humidity (Fig. 1

and 2). In contrast to real air conditions, the air exchange rate in the FLEC is higher (171

times/hour). This emission cell is designed to measure area specific emission rates of

general VOCs and separately the lowest aldehydes, formaldehydes and acetaldehyde, as

well as the lowest carboxylic acids, formic acid and acetic acid.

1 air inlet

2 air outlet

3 channel

4 sealing material

5 slit

1 Specimen is located in the subunit (stainless steel cylinder)

2 Sorbent tubes (e.g. stainless steel tubes filled with Tenax TA®)

Figure 1:Schematic of Field and Laboratory Emission Cell (FELC) (EN ISO 16000-‐10 Test cell method)

Figure 2: Application of the Field and Laboratory Emission Cell (FELC) combined with a subunit containing the specimen

Before each measurement on the specimen, a background air sample of the test chamber

was performed, to quantify any contribution of organic compounds from the clean air

system and the empty cell. The samples were prepared according to EN ISO 16000-‐11,

formatted (Ø14.8 cm) and stored in a conditioning room (23 ± 2°C and 50 ± 5%). Prior to

the tests fresh surfaces were planed and the edges were sealed with an alloy tape. The

stainless steel cell and subunit allowed a controlled climate at 23 ± 1°C and 50 ± 3% RH.

1

2


27

The exposed wood surface of 0.0177 m² was large relative to the cell volume of 35 ml and

ensured a high loading factor of 506 m²/m³ for sufficient analytical sensitivity. The inlet

airflow was set to 100 mL/min, which resulted in an inlet area specific airflow rate of

0.339 [m3/ (h*m2)] through the cell. Standard flow control pumps supplied an outlet

airflow of 80 mL/min for the duration of 960 min through an activated silica gel tube (SKC,

260/520 mg sorbent) for sampling acids. Aldehydes were sampled with the same air flow,

but only for the duration of 120 min in 2.4-‐DNPH adsorption cartridges. VOCs were

collected with 40 mL/ min for 80 min in Tenax® adsorbent tubes.

3.3 SET UP FOR DIVERSE GAS ANALYSIS

The Tenax® samples (200 mg) were desorbed (UltrA/ Unity, Markes Inc.) and detections

were carried out by mass spectrometry, using GC/ MS, 7890A GC and 5975C MS (Agilent

Technologies) and library spectra. Low aldehydes were identified by high-‐performance

liquid chromatography (HPLC; EN ISO 16000-‐3). The DNPH cartridges were extracted with

acetonitrile and analysed via HPLC using a variable wavelength detector (HPLC/ 1100

System, Agilent Technologies). The aldehyde content was automatically calculated from

the obtained peak area. Low acids separations were performed with an ion

chromatography system with a conductivity detector with ion suppression using an ion

exclusion chromatography column (Strömberg 2013). The measured concentration of

volatile compounds (Eq. 2) in the outlet air [µg/ m³] was converted (Eq. 3) into the area

specific emission rate [µg/ m² * h].

Concentration [µg/m3] = Peak area [ae] / (RF [ae/ng] x sample vol. [L]) / RRF (Eq. 2)

Area specific emission rate [µg/m2h] = Concentration [µg/m3] x 0.339 (Eq. 3)

RF = Toluene equivalent (value of control sample from internal calibration setup of SP)

RRF = Relative Response Factor (relative to toluene) expresses rate in compound specific amount

Area specific air flow rate (0.339)

4 RESULTS AND DISCUSSION

The emissions obtained from the micro-‐chamber measurements were described

separately for each species on the first and the third day (Fig.3). Low aldehydes, i.e.


28

formaldehyde (FA) and acetaldehyde (AA) were detected in the untreated specimens of

both species. Concerning the untreated, green samples of both species, hydrolysed acids

did not emit in greater amounts, due to the moisture content (>70%) of the untreated

samples. In addition the formation of formaldehyde was not catalysed through an acetic

environment. The content of terpenes and aldehydes, and thus the sum of VOCs (sum of

aldehydes > C2 and terpenes) for the impregnated and thermally modified samples, was

far greater than that of the untreated samples. However, these compounds possess very

little corrosivity towards materials like textiles, paper and metals.

Figure 3: Means of area specific emission rates of specimens (Fir and Alder, n = 2 /batch)


29

Contrary to expectation, identified compounds were refound after the thermal

modification and drying process. However, all variants of Fir samples did not show any

low acids, i.e. acetic and formic acid, neither at the first nor at the third day.

Unfortunately the results obtained from the Fir samples were not likely to give

information about the influence of the different modification parameters on the chemical

compounds. In contrast to the Fir samples, in the impregnated, thermally modified and

kiln-‐dried specimens of Alder no FA or AA values were detected. Due to aldehydes (> C2),

low amounts of VOC were detected in all thermally treated and dried variants of Alder

samples. As far as the detection limits for substances with high contamination potential

for individual display case construction materials were concerned, the low amount of

acidity and yet a missed formation of formaldehyde in the Alder samples were very

positive results.

5 CONCLUSIONS

The study considered direct emissions as well as secondary products, concerning the

formation of acids and aldehydes, caused by thermo-‐hydrolysis. It was found that the

FLEC is an appropriate instrumentation for the performance of the investigation of small-‐

sized samples, with a respectively low emission concentration. Similarly, the three

different methods of analysis (GC/MS, IC and HPLC) were essential for the investigations.

Reasonable adjustments were achieved in applying the appropriate method. With this

advanced modification process, especially the suppressed formation of formaldehyde and

the minimized amount of acids, the applicability of thermally modified timber products in

sensitive environments, e.g. health care institutions or museums, could be achieved.

6 REFERENCES

Birkeland M.J., Lorenz L., Wescott J.M., Frihart C.R. 2010: Determination of native (wood

derived) formaldehyde by the desiccator method in particelboards generated during

panel production. Holzforschung, Vol. 64,pp. 429-‐433, Walter de Gruyter, Berlin, New

York.


30

Carlson F.E., Phillips E.K., Tenhaeff S.C., Detlefsen W.D. 1995: Study of formaldehyde and

other organic emissions from pressing of laboratory oriented strandboard. Forest

Products Journal J.45, 71-‐77.

Englund F. 2010: Neutral materials in the museum environment: Emissions from

materials, SP Technical Research Institute of Sweden, Stockholm.

Roffael E., Hameed M., Kraft R. 2007: Bildung von Formaldehyd, Furfural und

Ameisensäure bei der thermohydrolytischen Behandlung von einigen monomeren

Zuckern (Xylose, Arabinose und Ga-‐lactose), Beitrag zu Entstehung von flüchtigen

organischen Verbindungen (VOC) beim Holzaufschluss für die MDF-‐Herstellung,

Holztechnologie, Bd. 48, Nr. 2, S. 15-‐18.

Schäfer M., Roffael E. 2000: On the formaldehyde release of wood. Holz als Roh-‐ und

Werkstoff 58, S. 321-‐322.

Stamm A.J. 1964: Wood and cellulose science. Ronald Press, New York.

Strömberg N. 2013: SP Method for carboxylic acids in air, SP Chemistry and Materials

Technology, Borås, Sweden.

ASTM D 5582-‐00 2006: Bestimmung der Formaldehydkonzentrationen aus Holzprodukten

mit einem Exsikkator, Ausgabedatum: 2000, reapproved: 2006, Beuth, Berlin.

CARB 2008: California Air Resources Board, California Environmental Protection Agency.

State of California, USA.

DIN EN 717-‐1 2004: Holzwerkstoffe -‐ Bestimmung der Formaldehydabgabe -‐ Teil 1:

Formaldehydabgabe nach der Prüfkammer-‐Methode, Beuth, Berlin.

DIN EN 717-‐2 1994: Holzwerkstoffe -‐ Bestimmung der Formaldehydabgabe -‐ Teil 2:

Formaldehydabgabe nach der Gasanalyse-‐Methode, Beuth, Berlin.

EN 120 1993: Holzwerkstoffe -‐ Bestimmung des Formaldehydgehaltes -‐

Extraktionsverfahren (genannt Perforatormethode), Beuth, Berlin.


31

ISO 16000-‐10 2006: Indoor air -‐-‐ Part 10: Determination of the emission of volatile organic

compounds from building products and furnishing -‐ Emission test cell method, SIS

Förlag AB, 118 80 Stockholm.


32

Application of FT-NIR for recognition of substances used for

conservation of wooden parquets of 19th century manor

houses located in South-Eastern Poland

Anna Rozanska1, Anna Sandak2

1 PhD student, Warsaw University of Life Sciences (SGGW), Nowoursynowska 166, 02-‐787

Warsaw, Poland, [email protected]

2 IVALSA Tree and Timber Institute, via Biasi 75, 38010 San Michele all’Adige (TN), Italy,

[email protected]

ABSTRACT

In antique palaces and manor houses, traditional surface finishing techniques were used.

The surfaces of antique wooden parquets were soaked with wax or with oils. Those

substances preserve wood and have a major influence on �

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