research article the effects of natural weathering on

Research ArticleThe Effects of Natural Weathering on Color Stability ofImpregnated and Varnished Wood Materials

Turkay Turkoglu1 Ergun Baysal2 and Hilmi Toker2

1Department of Forestry Koycegiz Vocational School Mugla Sitki Kocman University 48800 Mugla Turkey2Faculty of Technology Wood Science and Technology Mugla Sitki Kocman University 48000 Mugla Turkey

Correspondence should be addressed to Turkay Turkoglu turkayturkoglumuedutr

Received 10 February 2015 Revised 15 April 2015 Accepted 20 April 2015

Academic Editor Peter Majewski

Copyright copy 2015 Turkay Turkoglu et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

The aim of this study was to investigate effects of natural weathering on color stability of Scots pine (Pinus sylvestris L) andOriental beech (Fagus orientalis L) impregnated with some chemicals [tanalith-E (TN-E) adolit-KD5 (AD-KD5) and chromatedcopper arsenate (CCA)] and then varnished [synthetic varnish (SV) and polyurethane varnish (PV)] While applying varnishincreased lightness impregnation decreased lightness of the wood specimens before natural weathering Natural weathering causedgreenish bluish and dark color tones of the wood surface Total color change was increased with increasing exposure times innatural weathering Untreated (control) wood specimens exhibited higher color changes than the other wood specimens in allthe stages of natural weathering The total color changes of untreated Oriental beech specimens were less than untreated Scotspine specimens The color stability of impregnated and varnished wood specimens gave better results than untreated and solelyvarnished wood specimens after natural weatheringThe best color stability was obtained from both Oriental beech and Scots pinewood impregnated with TN-E before PV coating

1 Introduction

Wood is one of the most important natural materials usedfor aesthetic engineering and structural applications [1 2]Wood materials are usually exposed to solar radiation waterwind and dust during their useful life when used outdoor[3] Unfortunately wood is susceptible to environmentalfactors just like other biological materials [4 5] A varietyof different environmental factors degrade its main chemicalcomponents lignin cellulose and hemicelluloses [2 6 7]The depolymerization of lignin and cellulose leads to a reduc-tion in some physical chemical and biological properties ofwood [8] The main factor that causes the greatest changesin the wood surface properties during outdoor exposure issunlight [9ndash11] The photon energy in sunlight (ultravioletvisible and infrared light) is extremely harmful initiatinga wide variety of chemical changes in the wood surfaces[12] Weathering is the general term used to define thedegradation of materials exposed to the weather [13] initiallycausing changes in the wood surfacersquos color [14] Color is a

basic visual feature for wood and wood based products [15]Nevertheless wood can be chemically modified to minimizespecific problems such as moisture absorption microbialattack swelling and shrinkage as well as susceptibility tophotodegradation [16ndash18] Surface treatment of wood withinorganic chemicals and impregnation has been suggestedamong the effective methods to decrease the negative effectof weathering on wood [12 17 19] The application of clearcoating is the easiest and most common method for protect-ing wood against natural weathering [5 20] However thecoating thickness decreases with increasing weathering timeand a tissue deformation below the coating surface occursduring weathering [21] Impregnation with wood preserva-tives followed by the application of durable coatings or avarnishpaint makes wood more durable to photochemicaldegradation dimensional changes and biological organismsand increases the service life of treated wood [12 19 22 23]Chromated copper arsenate (CCA) has provided long-termprotection against weathering and erosion [24 25] but it isno longer being produced for use in most residential settings

Hindawi Publishing CorporationAdvances in Materials Science and EngineeringVolume 2015 Article ID 526570 9 pageshttpdxdoiorg1011552015526570

2 Advances in Materials Science and Engineering

because it contains chromium and arsenic Nowadays severalnew copper-based wood preservatives such as tanalith-E(TN-E) and adolit-KD5 (AD-KD5) are being used in theforest products industry instead of CCA It is generallyknown that new copper-based wood preservatives and var-nishes retard or prevent photodegradation [23] The effectof accelerated weathering on color characteristics of Scotspine and alder wood impregnated with alkylammoniumcompounds (AACS) CCA ammoniacal copper quat (ACQ1900 and ACQ 2200) TN-E 3491 and wolmanit CX-8 wasinvestigated by Temiz et al [8] Yalinkilic et al investigatedthe outdoor performance of Scots pine and chestnut woodtreated with chromium-copper-boron (CCB) and appliedwith polyurethane varnish (PV) or alkyd-based syntheticvarnish (SV) They reported that CCB impregnation greatlystabilized the surface color and reduced mass loss of woodIt was also claimed that preservative treatment followed by asurface coating system protected wood in long-term outdoorconditions [19] Another research about outdoor weatheringdurability of obeche red beech spruce and fir wood treatedwith CCB was carried out by Sell and Feist They found thatCCB-coated wood has high resistance and protective effectagainst weathering [26] The comparison of new copper-based wood preservatives with CCA and their performancetesting is important in determining consumer expectation ofthese new products

This study investigates the effect of natural weathering oncolor stability of Scots pine andOriental beech wood impreg-nated with copper-based wood preservatives including TN-E AD-KD5 and CCA and applied with PV or SV The effectof 3- and 6-month natural weathering on color stability wasevaluated

2 Materials and Methods

21 Materials

211 Preparation of Test Specimens and Chemicals Woodspecimens were prepared from air-dried sapwood of Scotspine and Oriental beech for impregnation treatment withdimensions of 10 (radial) times 100 (tangential) times 150 (lon-gitudinal)mm They were oven dried at 50 plusmn 5∘C untilconstant weight Wood specimens were impregnated withthree preservatives containing CCA AD-KD5 and TN-EAqueous solutions of impregnation chemicals were dissolvedin distilled water to a concentration of 4 percent pH degreesof impregnation solutions are 776 for CCA 839 for AD-KD5and 825 for TN-E An alkyd-based SV and a solvent-basedtwo-component PV were applied after the impregnationprocess in this study

22 Methods

221 Impregnation Process The wood specimens wereimpregnated with 4 percent aqueous solution of CCA AD-KD5 and TN-E according to the ASTM D1413-07e1 [27]All specimens were conditioned at 20∘C and 65 relativehumidity for two weeks before tests Calculating the amount

of preservative impregnation chemicals absorbed by thewood specimens as kilograms per cubic meter (kgm3) ofwood was done using the following formula

Retention(Kgm3) =

119866 times 119862

119881

times 10 (1)

where 119866 = (1198792minus 1198791) is grams of treatment solution

absorbed by the wood specimens (1198791is the weight of the

wood specimens before impregnation and 1198792is the weight

of the wood specimens after impregnation) 119862 is grams ofpreservative in 100 g of the treatment solution and 119881 isvolume of the wood specimen as cm3

222 Coating SV and PV were supplied by merchants andused according to the producerrsquos instructions The viscosityof the varnishes was determined according to the manufac-turerrsquos directions and was found to be 18 s (DIN 4 cup) at20 plusmn 2

∘C for both varnishes Hardener and thinner mixtureratios were determined according to the manufacturerrsquossuggestions The varnish was applied to all surfaces and sidesof the wood specimens with a spray gun according to theASTM D3023-98 standard [28] Filler was not used on thewood surfaces in order to avoid potential interference withthe surface characteristics of the wood Instead of using fillervarnish was applied twice for PV and 4 times for SV Thefirst coating applied to the wood surface was for filling thevoids and the second and upper coatings were applied for topcoating Sufficient time for layer settling was allowed betweensuccessive applications until the target retention of 100 gm2for the primer and 100 gm2 for the top coating was reachedcontrolled by consecutive weighing Specimens were left inambient conditions for 24 h according to the manufacturerrsquosrecommendations after the first coating and then surfaceswere gently sanded using a fine-grit sandpaper (220 grit) toobtain a smooth surface before the top coating After the topcoating of varnishwas applied to the surfaces specimenswereconditioned for 3 weeks [12]

223 Natural Weathering Wood specimens were preparedfor weathering exposure according to ASTM D7787 [29]They were exposed to weathering conditions during springand summer (from March to August) in 2011 The site issituated at Mugla Sitki Kocman University (37∘091015840N and28∘221015840E 670m above sea level) in Mugla Southern AegeanRegion of Turkey Weather conditions of Mugla duringweathering were given in Table 1 [30]

The exposure rack was positioned so that the exposedspecimens were at an angle of 45∘ facing south Wood spec-imens were set outside for weathering exposure accordingto ASTM G7G7M-13 [31] Exposure covered a period of6 months The wood specimens were removed at 3-monthintervals for performance evaluation The color parameterswere measured on the exposed surfaces of the wood speci-mens

224 Color Test The CIE 119871lowast119886lowast119887lowast color system was used tocompare exposure directions of natural weathering (Figure 1)

Advances in Materials Science and Engineering 3

Table 1 Weather conditions of Mugla fromMarch to August in 2011

Months Mar Apr May Jun Jul AugAverage temperature (∘C) 86 117 164 228 279 275The highest temperature (∘C) 199 217 291 359 384 381The lowest temperature (∘C) minus49 14 68 13 121 135Sunbathing time (hour) 54 55 68 10 112 104The number of the rainy days 11 17 9 6 0 0Rainfall per month (kgm2) 298 804 594 174 0 0Humidity () 746 752 678 536 388 392

WhiteL = 100

Green

Blue

BlackL = 0

Yellow

Red

+a

+bminusa

minusb

Figure 1 The CIE 119871lowast119886lowast119887lowast color space

The 119871lowast axis represents the lightness while 119886lowast and 119887lowast arethe chromaticity coordinates The +119886lowast and minus119886lowast parametersrepresent red and green respectively The +119887lowast parameterrepresents yellow whereas minus119887lowast represents blue 119871lowast can varyfrom 100 (white) to zero (black) [32] The colors of thespecimens were measured by a colorimeter (X-Rite SP SeriesSpectrophotometer) before and after natural weatheringThemeasuring spot was adjusted to be equal to or not more thanone-third of the distance from the centre of this area to thereceptor field stops The color difference (Δ119864lowast) was deter-mined for each wood according to ASTM D2244-14 [33]

Δ119886lowast

= 119886119891

lowast

minus 119886119894

lowast

Δ119887lowast

= 119887119891

lowast

minus 119887119894

lowast

Δ119871lowast

= 119871119891

lowast

minus 119871119894

lowast

(Δ119864lowast

) = ((Δ119886lowast

)2

+ (Δ119887lowast

)2

+ (Δ119871lowast

)2

)

12

(2)

where Δ119886lowast Δ119887lowast and Δ119871lowast are the changes between the initialand final interval values Ten replications were made for eachgroup

3 Results and Discussion

In this study synthetic or polyurethane varnish was appliedto Scots pine and Oriental beech wood specimens after

Table 2 Retentions of wood specimens

Impregnationsolution

Concentration ()Retention (Kgm3)

Scots pine Orientalbeech

CCA 4 327 276AD-KD5 4 307 231TN-E 4 355 288

being impregnated with three different chemicals except forthe control specimens The wood specimens were exposedto natural weathering for two periods 3 months and 6months The effects of natural weathering on color stabilityof impregnated and varnished wood materials are evaluatedin this section Retentions of different impregnation solutionson Scots pine and Oriental beech wood are given in Table 2

Retentions were calculated as 307 to 355 kgm3 in Scotspine and 231 to 288 kgm3 in Oriental beech The highestretention amounts determined in Scots pine and Orientalbeech treated with TN-E were 355 kgm3 and 288 kgm3respectively The lowest retention amounts determined inScots pine and Oriental beech treated with AD-KD5 were307 kgm3 and 231 kgm3 respectively

31 Effect of Natural Weathering on Color Stability Table 3presents 119871lowast 119886lowast and 119887lowast values of untreated (control) solelyvarnished and impregnated and varnished Oriental beechspecimens before natural weathering and also illustrates thevalues of change for all three color parameters (Δ119871lowast Δ119886lowastand Δ119887lowast) as well as the total color changes (Δ119864lowast) of thewood specimens after 3 months and 6 months of naturalweathering

Before natural weathering while 119871lowast value of untreated(control) Oriental beech wood specimens was 6230 119871lowastvalues of solely PV and solely SV coated wood specimenswere 6807 and 6354 respectively Applying varnish madethe wood color lighter and increased the yellowness of thecolor on the wood surface The decrease in 119871lowast value ofwood specimens indicates that the specimens become darker[12] Impregnated and varnished wood specimens becomeslightly darker than control wood specimens However woodspecimens impregnated with TN-E before varnish coatingwere darker compared to the others The darkening ofimpregnated and varnished wood specimens might be due tothe impregnation materials While 119886lowast values changed from


Table3Th

ecolor

changeso

fOrie

ntalbeechbefore

andaft

ernaturalw

eathering

nBe

fore

naturalw

eathering

Afte

r3-m

onth

naturalw

eathering

Afte

r6-m

onth

naturalw

eathering

La

bΔL

Δa

Δb

ΔE

ΔL

Δa

Δb

ΔE

Mean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDCon

trol

106230

760

1078

138

2178

301minus98

414

0minus98

312

699

413

11710

260minus1935

255minus123

187minus863

105

2450

314

PV10

6807

735

1260

120

2704

419

892

123minus537

062

936

120

1400

193minus1478

189minus96

613

3minus1007

109

2033

234

SV10

6354

546

1274

148

2811

371

787

083minus565

066

845

123

1286

149minus1318

192minus1016

118minus97

5084

1929

224

CCA+PV

106053

557

1215

156

2851

393

778

095minus353

045

825

125

1188

145minus1363

207minus78

5096minus753

069

1744

241

AD-K

D5+PV

105427

613

1477

142

2873

448

760

101minus339

053

726

089

1104

147minus1135

140minus94

112

5minus518

059

1563

244

TN-E

+PV

103869

352

314

043

1006

139

586

071minus397

055

695

077

992

120minus587

065minus681

082minus695

063

1136

157

CCA+SV

106146

510

1190

142

2896

489

692

078minus548

065

584

066

1058

120minus1302

147minus886

091

873

072

1801

214

AD-K

D5+SV

105821

646

1243

170

2750

377

683

096minus538

074

589

077

1050

148minus1056

138minus91

312

9minus78

1087

1600

219

TN-E

+SV

103551

440

283

033

887

122

655

081minus483

057

586

073

1003

124minus685

085minus719

089minus72

4090

1229

145

Note119899the

numbero

fmeasuredsamplesM

ean(119883

)averagev

alue

ofmeasurements

SDstand

arddeviation


283 to 1477 119887lowast values changed from 887 to 2896 beforenatural weathering Oriental beech wood specimens hadlight yellowish and reddish color before natural weatheringThe pale yellow color of the control specimens is primarilyreflective of the color of the lignin component of wood [34]

After 3-month natural weatheringΔ119886lowast valueswere foundto be minus339 to minus983The negative Δ119886lowast values showed that thewood surface turned from red to green Δ119887lowast values changedfrom 584 to 994 Positive Δ119887lowast values indicate that woodspecimens maintained a yellowish tone Δ119871lowast is the mostsensitive parameter of thewood surface quality [35] but therewas a dramatic decline in Δ119871lowast values after 3-month naturalweatheringTherefore the wood surface became darker thanthe values before natural weathering

After 6-month natural weathering the Δ119871lowast value ofcontrol wood specimens decreased substantially Depolymer-ization of the lignin can also bring about the darkening ofthe wood surface [8 12 36] According to the Δ119887lowast valuesthe wood surface changed from yellow to blue after 6-monthnatural weatheringThe decrease of yellowness with weather-ing time may be attributed to the reduction of paraquinones(chromophoric structures) to hydroquinones which resultsin photobleaching [37] The least change in Δ119887lowast value wasAD-KD5 with PV coated for Oriental beech wood specimensafter 6-month natural weathering TN-E impregnation beforevarnishing resulted in the leastΔ119886lowast changesThe greatestΔ119886lowastchanges for Oriental beech wood specimens occurred in thecontrol specimens at the end of 6 months

The color changes of Scots pine before and after naturalweathering are shown in Table 4 119871lowast value of untreated(control) Scots pine wood specimens was 7052 Lightness(119871lowast) of wood specimens impregnated and varnished isslightly lower than solely varnished wood specimens beforenatural weathering In other words while the lightness ofsolely varnished wood specimens increased impregnatedand varnished wood specimens became darkener 119871lowast valuesof wood specimens impregnated and varnished and solelyvarnishedwere observed from4502 to 7885 119886lowast and 119887lowast valueswere found positive before natural weathering However theimpregnation materials decreased the red color tone valuein wood materials [38] It is reported that the impregnationof some softwoods with some chemicals has increased theyellow color tone [39] Baysal et al also reported that threecolor parameters (119871lowast 119886lowast and 119887lowast) of Scots pine decreasedafter the AD-KD5 impregnation process [40] Our results arein agreement with these researchersrsquo findings After 3-monthnatural weathering Δ119886lowast and Δ119887lowast values were found to havepositive values In other words yellow and red tone of woodspecimens had not changed markedly However Δ119871lowast valuesof untreated (control) Scots pine wood specimens decreasedreasonably after 3-month natural weathering Although Δ119871lowastis the most sensitive parameter Δ119871lowast values of untreated(control) Scots pine wood specimens decreased considerablyafter 6-month natural weathering The lightness values ofall the specimens decreased after natural weathering butlightness of the control specimens was more than the othersWhile the tone of Scots pine wood specimens changed fromred to green on the red-green scale they changed fromyellow to blue on yellow-blue scale after 6-month natural

0

5

10

15

20

25

Con

trol

PV SV

CCA+

PV

AD

-KD5+

PV

TN-E

+PV

CCA+

SV

AD

-KD5+

SV

TN-E

+SV

Three-month natural weatheringSix-month natural weathering

Figure 2 Total color changes (Δ119864) of Oriental beech after 3- and6-month natural weathering Note it is drawn by using the averagevalue of Δ119864 See Table 3 for standard deviations

weathering Ruther and Jelle investigated color changes ofwooden boards outdoors both on a test house and in thelaboratory They measured in rack before natural weatheringthat 119871lowast 119886lowast and 119887lowast values of Scots pine heartwood woodspecimens were 756 102 and 102 respectively and afternatural weathering three color parameters (119871lowast 119886lowast and 119887lowast)were found to be 496 minus25 and 53 respectively [41] Theleast Δ119886lowast changes occurred with TN-E impregnation beforePV varnishing and AD-KD5 with SV coating resulted in thegreatest Δ119886lowast changes for Scots pine wood specimens after 6-month natural weathering The Scots pine wood specimensimpregnated with TN-E had minimal Δ119871lowast changes for bothSV and PV coated after 6-month natural weathering Totalcolor changes (Δ119864lowast) of Oriental beech after 3- and 6-monthnatural weathering are shown in Figure 2

While the Δ119864lowast values of Oriental beech wood specimenschanged from 992 to 1710 after 3-month natural weatheringat end of 6 months Δ119864lowast values changed from 1136 to 2450for Oriental beech wood specimens The highest Δ119864lowast wasobserved on the untreated (control) Oriental beech speci-mens Untreated Oriental beech wood specimens exhibitedhigher color changes than coated specimens in 3- and 6-month natural weathering However Fufa et al reportedthat color changes of the varnished specimens become thehighest in untreated (control) specimens at long periods ofnatural weathering [42] Our results show that the trend ofdiscoloration of impregnated and varnished specimens waslower than the varnished and control specimens Total colorchanges (Δ119864) of Scots pine after 3- and 6-month naturalweathering are shown in Figure 3

The highest Δ119864lowast was observed on the untreated (control)Scots pine after 3- and 6-month natural weathering Whilethe Δ119864lowast values of Scots pine wood specimens changed from1010 to 2202 after 3-month natural weathering Δ119864lowast valuesof Scots pine wood specimens changed from 1203 to 3315after 6-month natural weathering Fufa et al reported thatuntreated specimens exhibited higher color changes than


Table4Th

ecolor

changeso

fScotspine

before

andaft

ernaturalw

eathering

nBe

fore

naturalw

eathering

Afte

r3-m

onth

naturalw

eathering

Afte

r6-m

onth

naturalw

eathering

La

bΔL

Δa

Δb

ΔE

ΔL

Δa

Δb

ΔE

Mean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDCon

trol

107052

931

652

083

2781

423minus2149

327

425

054

222

027

2202

282minus3007

427minus426

052minus132

169

3315

491

PV10

7885

1009

766

088

3236

447minus1371

189

584

085

592

064

1603

152minus2365

326minus17

018minus884

102

2531

367

SV10

7544

1101

741

086

3256

378minus1283

149

581

065

434

037

1474

171minus2101

243minus43

037minus685

079

2251

297

CCA+PV

10712

1082

625

080

2950

360minus1212

131

412

057

521

048

1382

181minus1849

226minus119

011minus384

049

1892

261

AD-K

D5+PV

107394

909

835

130

4124

548minus1117

163

511

080

567

064

1353

130minus1746

232minus18

8021minus526

082

1833

286

TN-E

+PV

104502

518

431

059

1249

151minus737

089

355

049

592

054

1010

141minus824

103minus643

059minus595

094

1203

166

CCA+SV

107098

802

696

083

2851

294minus1039

117

528

063

795

066

1411

168minus1737

196minus564

047minus621

074

1929

230

AD-K

D5+SV

107282

954

861

118

4206

593minus1017

143

354

048

776

086

1327

182minus1588

224minus368

041minus634

087

1753

240

TN-E

+SV

104771

592

326

038

1586

197minus624

077

298

035

765

095

1031

122minus1134

141minus637

079minus585

069

1426

168

Note119899the

numbero

fmeasuredsamplesM

ean(119883

)averagev

alue

ofmeasurements

SDstand

arddeviations


0

5

10

15

20

35

30

25

Con

trol

PV SV

CCA+

PV

AD

-KD5+

PV

TN-E

+PV

CCA+

SV

AD

-KD5+

SV

TN-E

+SV


Figure 3 Total color changes (Δ119864) of Scots pine after 3- and 6-month natural weathering Note it is drawn by using the averagevalue of Δ119864 See Table 4 for standard deviations

varnished or coated specimens in the short period of naturalweathering [42]However for longer performance of coatingsat exterior applications improvements of the coatings arecrucial It is known that the maintenance of wood coatingsin exterior use is crucial to the performance and durabilityduring weathering [43]

As the result the best color stability was TN-E withPV coating for both Oriental beech and Scots pine woodspecimens TN-E treatments both slowed down photodegra-dation by retarding the formation of carbonyl groups Thelight resistance of TN-E-treated wood likely results fromCu (II) chelating with functional groups in wood Thesechelates can photostabilize wood and retard the formationof carbonyl groups [8 44] Otherwise solely PV coating didnot contribute to stabilizing the wood color UV light has acrucial role in the weathering degradation of polyurethanecoatings [45] Solely PV coating generally produced slightlybetter color stability than solely SV coating after naturalweathering However Baysal et al found that in specimenswhere color changes of impregnated and varnished Scotspine after accelerated weathering occurred solely SV coatedwood specimens were observed to have better color stabilitythan PV [12] This situation can be explained because woodspecimens in our study were exposed to natural weatherconditions such as sunlight and rain Moreover Budakci etal found that the color stability of wood specimens afterageing tests could be ordered in the following way acrylicvarnish gt polyurethane varnish gt cellulosic varnish [46]Theimpregnated wood with copper-based formulations beforePV coating was more effective in stabilizing wood color thanPV or SV coating alone [12] Wood specimens impregnatedwith TN-E before PV coating showed better color stabilitythan the others in this study Double treatment of wood withchemicals and varnishes is necessary to extend the servicelife of a wood Baysal and Grull et al recommended thatthe application of a maintenance coat is important [22 43]The color change is attributed to the carbonyl groups of

the conjugated ketones aldehydes and quinines resultingfrom lignin and other compound modifications [47] andit depends on the formation of carbonyl groups generatedduring photodegradation of the wood [9] TN-E whichincludes copper might reduce photodegradation by retardingthe formation of carbonyl groups and delignification Similarfindings were also obtained on copper-based formulations[8 47] Copper forms certain complexes with wood com-ponents such as copper-cellulose complexes copper-lignincomplexes and crystalline or amorphous inorganicorganiccopper compounds and reduces the degradation of the woodsurface from weathering factors [8 47] Wood ion complexesformed at the wood surfaces can provide the wood surfacewith resistance by blocking the free phenolic groups [47]Similar ion complexes can be formed with copper-based for-mulations andwood components and these complexesmightreduce radials which stabilize the color of the wood [48]

4 Conclusions

Wood materials used in exterior applications are exposedto several climate factors including solar radiation watertemperature changes wind and erosion [49] These factorsaffect the color stability of wood in particular This studyinvestigated the effect of natural weathering on color stabilityof impregnated and varnished Scots pine and Oriental beechwoodWhile TN-E AD-KD5 andCCAwere used as impreg-nation chemicals polyurethane and synthetic varnishes wereused as varnish in this study It was observed that theretention of Scots pine is higher than the retention ofOrientalbeech

Initially Scots pine and Oriental beech control woodspecimens had lighter natural reddish and yellowish colortones Varnishing them increased lightness yellowness andredness of the color of the wood surface but impregnatingthemdecreased lightness of thewood specimens compared tocontrol specimens The lightness values of all the specimensdecreased within natural weathering However untreated(control) wood specimens exhibited higher color changesthan the other specimens in all stages of natural weatheringΔ119886lowast and Δ119887lowast decreased with increasing exposure times in

natural weathering for both Scots pine and Oriental beechwood specimens

It can be concluded that untreated (control) solelyvarnished and both impregnated and varnished wood spec-imens shifted from red to green on the red-green scale andfrom yellow to blue on yellow-blue scale with increasingexposure times in natural weathering The highest total colorchange was observed on the untreated (control) Scots pineafter 3- and 6-month natural weathering The total colorchanges of untreated Oriental beech specimen were less thanthat of untreated Scots pine specimens Finally the best colorstability was obtained by impregnation with TN-E before PVcoating for both Oriental beech and Scots pine wood spec-imens after the natural weathering The impregnated woodwith copper-based formulations before PV coating was moreeffective in stabilizing wood color The photostabilization ofwood by copper-based impregnationmay be explained by the


retarding of the formation of carbonyl groups and reduceddelignification during weathering

Conflict of Interests

The authors declare no conflict of interests

References

[1] I-U Bhat H P S Abdul Khalil K B Awang I O Bakareand A M Issam ldquoEffect of weathering on physical mechanicaland morphological properties of chemically modified woodmaterialsrdquo Materials amp Design vol 31 no 9 pp 4363ndash43682010

[2] B Lesar M Pavlic M Petric A S Skapin and M HumarldquoWax treatment of wood slows photodegradationrdquo PolymerDegradation and Stability vol 96 no 7 pp 1271ndash1278 2011

[3] W C Feist R M Rowell and R J Barbour ldquoOutdoor woodweathering and protectionrdquo Advances in Chemistry Series vol225 pp 263ndash298 1990

[4] R S Williams and W C Feist ldquoWater repellents and water-repellent preservatives for woodrdquo General Technical ReportFPL-GTR-109 Forest Products LaboratoryMadisonWisUSA1999

[5] S-T Chang and P-L Chou ldquoPhotodiscoloration inhibition ofwood coated with UV-curable acrylic clear coatings and itselucidationrdquo Polymer Degradation and Stability vol 69 no 3pp 355ndash360 2000

[6] K J Schmalzl and P D Evans ldquoWood surface protectionwith some titanium zirconium and manganese compoundsrdquoPolymer Degradation and Stability vol 82 no 3 pp 409ndash4192003

[7] M Jebrane G Sebe I Cullis and P D Evans ldquoPhotostabilisa-tion of wood using aromatic vinyl estersrdquo Polymer Degradationand Stability vol 94 no 2 pp 151ndash157 2009

[8] A Temiz U C Yildiz I Aydin M Eikenes G Alfredsen andG Colakoglu ldquoSurface roughness and color characteristics ofwood treated with preservatives after accelerated weatheringtestrdquo Applied Surface Science vol 250 no 1ndash4 pp 35ndash42 2005

[9] K K Pandey ldquoStudy of the effect of photo-irradiation on thesurface chemistry of woodrdquo Polymer Degradation and Stabilityvol 90 no 1 pp 9ndash20 2005

[10] Y Kataoka M Kiguchi R S Williams and P D Evans ldquoVioletlight causes photodegradation ofwoodbeyond the zone affectedby ultraviolet radiationrdquoHolzforschung vol 61 no 1 pp 23ndash272007

[11] L Tolvaj L Persze and L Albert ldquoThermal degradation ofwood during photodegradationrdquo Journal of Photochemistry andPhotobiology B Biology vol 105 no 1 pp 90ndash93 2011

[12] E Baysal E Dizman Tomak M Ozbey and E Altin ldquoSurfaceproperties of impregnated and varnished Scots pine wood afteraccelerated weatheringrdquo Coloration Technology vol 130 no 2pp 140ndash146 2014

[13] R S Williams Handbook of Wood Chemistry and Wood Com-posites Weathering of Wood Forest Products LaboratoryMadison Wis USA 2005

[14] O Ozgenc S Hiziroglu and U C Yildiz ldquoWeathering proper-ties of wood species treated with different coating applicationsrdquoBioResources vol 7 no 4 pp 4875ndash4888 2012

[15] I Aydin and G Colakoglu ldquoEffects of surface inactivationhigh temperature drying and preservative treatment on surface

roughness and colour of alder and beech woodrdquoApplied SurfaceScience vol 252 no 2 pp 430ndash440 2005

[16] P D Evans A F A Wallis and N L Owen ldquoWeathering ofchemically modified wood surfacesrdquo Wood Science and Tech-nology vol 34 no 2 pp 151ndash165 2000

[17] A Temiz N Terziev M Eikenes and J Hafren ldquoEffect ofacceleratedweathering on surface chemistry ofmodifiedwoodrdquoApplied Surface Science vol 253 no 12 pp 5355ndash5362 2007

[18] J Miklecic and V Jirous-Rajkovic ldquoAccelerated weathering ofcoated and uncoated beech wood modified with citric acidrdquoDrvna Industrija vol 62 no 4 pp 277ndash282 2011

[19] M K Yalinkilic R Ilhan Y Imamura et al ldquoWeathering dura-bility of CCB-impregnated wood for clear varnish coatingsrdquoJournal of Wood Science vol 45 no 6 pp 502ndash514 1999

[20] R Schwalm L Hauszligling W Reich E Beck P Enenkel andK Menzel ldquoTuning the mechanical properties of UV coatingstowards hard and flexible systemsrdquoProgress inOrganic Coatingsvol 32 no 1-4 pp 191ndash196 1997

[21] S Saha D Kocaefe C Krause and T Larouche ldquoEffect oftitania and zinc oxide particles on acrylic polyurethane coatingperformancerdquo Progress in Organic Coatings vol 70 no 4 pp170ndash177 2011

[22] E Baysal ldquoSome physical properties of varnish coated woodpreimpregnated with copper-chromated boron (CCB) after 3months of weathering exposure in southern eagen sea regionrdquoWood Research vol 53 no 1 pp 43ndash54 2008

[23] M Nejad and P Cooper ldquoExterior wood coatings Part-1performance of semitransparent stains on preservative-treatedwoodrdquo Journal of Coatings Technology Research vol 8 no 4 pp449ndash458 2011

[24] W C Feist and A S Ross ldquoPerformance and durabilityof finishes on previously coated CCA-treated woodrdquo ForestProducts Journal vol 45 no 9 pp 29ndash36 1995

[25] V Jirous-Rajkovic A Bogner and D Radovan ldquoThe efficiencyof various treatments in protecting wood surfaces againstweatheringrdquo Surface Coatings International Part B CoatingsTransactions vol 87 no 1 pp 15ndash19 2004

[26] J Sell and W C Feist ldquoWeathering behavior of chromium-copper-boron treated woodrdquo Holz als Roh- und Werkstoff vol43 pp 518ndash523 1985

[27] ASTM D1413-07e1 ldquoStandard test method for wood preserva-tives by laboratory soil-block culturesrdquo inAnnual Book of ASTMStandards ASTM West Conshohocken Pa USA 2007

[28] ASTM ldquoASTM D3023-98 Standard practice for determinationof resistance of factory-applied coatings on wood products tostains and reagentsrdquo inAnnual Book of ASTM Standards ASTMInternational West Conshohocken Pa USA 2013

[29] ASTM D7787D7787M-13 ldquoStandard practice for selectingwood substrates for weathering evaluations of architecturalcoatingsrdquo in Annual Book of ASTM Standards ASTM WestConshohocken Pa USA 2013

[30] Turkish State Meteorological Service Database Meteorologicaldata 2011 httpwwwmgmgovtr

[31] ASTM G7G7M-13 ldquoStandard practice for atmospheric envi-ronmental exposure testing of nonmetallic materialsrdquo inAnnual Book of ASTM Standards ASTM West ConshohockenPa USA 2013

[32] X ZhangPhoto-resistance of alkylammonium compound treatedwood [MS thesis] University of British Columbia VancouverCanada 2003


[33] ASTM International ldquoASTM D2244-14 Standard practice forcalculation of color tolerances and color differences frominstrumentally measured color coordinatesrdquo in Annual Bookof ASTM Standards ASTM International West ConshohockenPa USA 2014

[34] S Butylina M Hyvarinen and T Karki ldquoA study of surfacechanges of wood-polypropylene composites as the result ofexterior weatheringrdquo Polymer Degradation and Stability vol 97no 3 pp 337ndash345 2012

[35] E Baysal ldquoSurface characteristics of CCA treated scots pineafter accelerated weatheringrdquoWood Research vol 57 no 3 pp375ndash382 2012

[36] S C Ghosh HMilitz and CMai ldquoNatural weathering of scotspine (Pinus sylvestris L) boards modified with functionalisedcommercial silicone emulsionsrdquo BioResources vol 4 no 2 pp659ndash673 2009

[37] M Muasher and M Sain ldquoThe efficacy of photostabilizers onthe color change of wood filled plastic compositesrdquo PolymerDegradation and Stability vol 91 no 5 pp 1156ndash1165 2006

[38] H Keskin M Atar and A Ketizmen ldquoImpacts of impregnationwith boric acid and borax on the red colour tone of somehardwoods and varnishesrdquoAfrican Journal of Biotechnology vol8 no 16 pp 3958ndash3963 2009

[39] M Atar H Keskin and M H Colakoglu ldquoEffects of impreg-nation with imersol-AQUA on yellow color tone of somesoftwoods and varnishesrdquo Journal of Applied Polymer Sciencevol 103 no 2 pp 1048ndash1054 2007

[40] E Baysal S Degirmentepe H Toker and T Turkoglu ldquoSomemechanical and physical properties of AD-KD 5 impregnatedand thermally modified Scots pine woodrdquo Wood Research vol59 no 2 pp 283ndash296 2014

[41] P Ruther and B P Jelle ldquoColor changes of wood and wood-based materials due to natural and artificial weatheringrdquoWoodMaterial Science amp Engineering vol 8 no 1 pp 13ndash25 2013

[42] S M Fufa B P Jelle P J Hovde and P M Roslashrvik ldquoCoatedwooden claddings and the influence of nanoparticles on theweathering performancerdquo Progress in Organic Coatings vol 75no 1-2 pp 72ndash78 2012

[43] G Grull B Forsthuber F Tscherne and I Spitaler ldquoWeatheringindicator for artificial and natural weathering ofwood coatingsrdquoEuropean Journal of Wood and Wood Products vol 72 pp 681ndash684 2014

[44] O Ozgenc and U C Yildiz ldquoSurface characteristics of woodtreated with new generation preservatives after artificial weath-eringrdquoWood Research vol 59 no 4 pp 605ndash616 2014

[45] X F Yang D E Tallman G P Bierwagen S G Crolland S Rohlik ldquoBlistering and degradation of polyurethanecoatings under different accelerated weathering testsrdquo PolymerDegradation and Stability vol 77 no 1 pp 103ndash109 2002

[46] M Budakci D S Korkut and R Esen ldquoThe color changes onvarnish layers after accelerated aging through the hot and cold-check testrdquo African Journal of Biotechnology vol 9 no 24 pp3595ndash3602 2010

[47] S Grelier A Castellan and D P Kamdem ldquoPhotoprotection ofcopper-amine-treated pinerdquoWood and Fiber Science vol 32 no2 pp 196ndash202 2000

[48] S Schmid R D Webster and P D Evans ldquoThe use of ESRSpectroscopy to assess the photostabilising effects of woodpreservativesrdquo in Proceedings of the International ResearchGroup on Wood Preservation Conference Document IRGWP00-20186 Kona Hawaii USA May 2000

[49] B George E Suttie A Merlin and X Deglise ldquoPhotodegra-dation and photostabilisation of woodmdashthe state of the artrdquoPolymer Degradation and Stability vol 88 no 2 pp 268ndash2742005

Submit your manuscripts athttpwwwhindawicom

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CorrosionInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Polymer ScienceInternational Journal of



CeramicsJournal of


CompositesJournal of

NanoparticlesJournal of



International Journal of

Biomaterials


NanoscienceJournal of

TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

CrystallographyJournal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Smart Materials Research



MetallurgyJournal of


BioMed Research International

MaterialsJournal of


Nano

materials


Journal ofNanomaterials


because it contains chromium and arsenic Nowadays severalnew copper-based wood preservatives such as tanalith-E(TN-E) and adolit-KD5 (AD-KD5) are being used in theforest products industry instead of CCA It is generallyknown that new copper-based wood preservatives and var-nishes retard or prevent photodegradation [23] The effectof accelerated weathering on color characteristics of Scotspine and alder wood impregnated with alkylammoniumcompounds (AACS) CCA ammoniacal copper quat (ACQ1900 and ACQ 2200) TN-E 3491 and wolmanit CX-8 wasinvestigated by Temiz et al [8] Yalinkilic et al investigatedthe outdoor performance of Scots pine and chestnut woodtreated with chromium-copper-boron (CCB) and appliedwith polyurethane varnish (PV) or alkyd-based syntheticvarnish (SV) They reported that CCB impregnation greatlystabilized the surface color and reduced mass loss of woodIt was also claimed that preservative treatment followed by asurface coating system protected wood in long-term outdoorconditions [19] Another research about outdoor weatheringdurability of obeche red beech spruce and fir wood treatedwith CCB was carried out by Sell and Feist They found thatCCB-coated wood has high resistance and protective effectagainst weathering [26] The comparison of new copper-based wood preservatives with CCA and their performancetesting is important in determining consumer expectation ofthese new products

This study investigates the effect of natural weathering oncolor stability of Scots pine andOriental beech wood impreg-nated with copper-based wood preservatives including TN-E AD-KD5 and CCA and applied with PV or SV The effectof 3- and 6-month natural weathering on color stability wasevaluated

2 Materials and Methods

21 Materials

211 Preparation of Test Specimens and Chemicals Woodspecimens were prepared from air-dried sapwood of Scotspine and Oriental beech for impregnation treatment withdimensions of 10 (radial) times 100 (tangential) times 150 (lon-gitudinal)mm They were oven dried at 50 plusmn 5∘C untilconstant weight Wood specimens were impregnated withthree preservatives containing CCA AD-KD5 and TN-EAqueous solutions of impregnation chemicals were dissolvedin distilled water to a concentration of 4 percent pH degreesof impregnation solutions are 776 for CCA 839 for AD-KD5and 825 for TN-E An alkyd-based SV and a solvent-basedtwo-component PV were applied after the impregnationprocess in this study

22 Methods

221 Impregnation Process The wood specimens wereimpregnated with 4 percent aqueous solution of CCA AD-KD5 and TN-E according to the ASTM D1413-07e1 [27]All specimens were conditioned at 20∘C and 65 relativehumidity for two weeks before tests Calculating the amount

of preservative impregnation chemicals absorbed by thewood specimens as kilograms per cubic meter (kgm3) ofwood was done using the following formula

Retention(Kgm3) =

119866 times 119862

119881

times 10 (1)

where 119866 = (1198792minus 1198791) is grams of treatment solution

absorbed by the wood specimens (1198791is the weight of the

wood specimens before impregnation and 1198792is the weight

of the wood specimens after impregnation) 119862 is grams ofpreservative in 100 g of the treatment solution and 119881 isvolume of the wood specimen as cm3

222 Coating SV and PV were supplied by merchants andused according to the producerrsquos instructions The viscosityof the varnishes was determined according to the manufac-turerrsquos directions and was found to be 18 s (DIN 4 cup) at20 plusmn 2

∘C for both varnishes Hardener and thinner mixtureratios were determined according to the manufacturerrsquossuggestions The varnish was applied to all surfaces and sidesof the wood specimens with a spray gun according to theASTM D3023-98 standard [28] Filler was not used on thewood surfaces in order to avoid potential interference withthe surface characteristics of the wood Instead of using fillervarnish was applied twice for PV and 4 times for SV Thefirst coating applied to the wood surface was for filling thevoids and the second and upper coatings were applied for topcoating Sufficient time for layer settling was allowed betweensuccessive applications until the target retention of 100 gm2for the primer and 100 gm2 for the top coating was reachedcontrolled by consecutive weighing Specimens were left inambient conditions for 24 h according to the manufacturerrsquosrecommendations after the first coating and then surfaceswere gently sanded using a fine-grit sandpaper (220 grit) toobtain a smooth surface before the top coating After the topcoating of varnishwas applied to the surfaces specimenswereconditioned for 3 weeks [12]

223 Natural Weathering Wood specimens were preparedfor weathering exposure according to ASTM D7787 [29]They were exposed to weathering conditions during springand summer (from March to August) in 2011 The site issituated at Mugla Sitki Kocman University (37∘091015840N and28∘221015840E 670m above sea level) in Mugla Southern AegeanRegion of Turkey Weather conditions of Mugla duringweathering were given in Table 1 [30]

The exposure rack was positioned so that the exposedspecimens were at an angle of 45∘ facing south Wood spec-imens were set outside for weathering exposure accordingto ASTM G7G7M-13 [31] Exposure covered a period of6 months The wood specimens were removed at 3-monthintervals for performance evaluation The color parameterswere measured on the exposed surfaces of the wood speci-mens

224 Color Test The CIE 119871lowast119886lowast119887lowast color system was used tocompare exposure directions of natural weathering (Figure 1)




WhiteL = 100

Green

Blue

BlackL = 0

Yellow

Red

+a

+bminusa

minusb



Δ119886lowast

= 119886119891

lowast

minus 119886119894

lowast

Δ119887lowast

= 119887119891

lowast

minus 119887119894

lowast

Δ119871lowast

= 119871119891

lowast

minus 119871119894

lowast

(Δ119864lowast

) = ((Δ119886lowast

)2

+ (Δ119887lowast

)2

+ (Δ119871lowast

)2

)

12

(2)








CCA 4 327 276AD-KD5 4 307 231TN-E 4 355 288






Table3Th

ecolor

changeso

fOrie

ntalbeechbefore

andaft

ernaturalw

eathering

nBe

fore

naturalw

eathering

Afte

r3-m

onth

naturalw

eathering

Afte

r6-m

onth

naturalw

eathering

La

bΔL

Δa

Δb

ΔE

ΔL

Δa

Δb

ΔE

Mean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDCon

trol

106230

760

1078

138

2178

301minus98

414

0minus98

312

699

413

11710

260minus1935

255minus123

187minus863

105

2450

314

PV10

6807

735

1260

120

2704

419

892

123minus537

062

936

120

1400

193minus1478

189minus96

613

3minus1007

109

2033

234

SV10

6354

546

1274

148

2811

371

787

083minus565

066

845

123

1286

149minus1318

192minus1016

118minus97

5084

1929

224

CCA+PV

106053

557

1215

156

2851

393

778

095minus353

045

825

125

1188

145minus1363

207minus78

5096minus753

069

1744

241

AD-K

D5+PV

105427

613

1477

142

2873

448

760

101minus339

053

726

089

1104

147minus1135

140minus94

112

5minus518

059

1563

244

TN-E

+PV

103869

352

314

043

1006

139

586

071minus397

055

695

077

992

120minus587

065minus681

082minus695

063

1136

157

CCA+SV

106146

510

1190

142

2896

489

692

078minus548

065

584

066

1058

120minus1302

147minus886

091

873

072

1801

214

AD-K

D5+SV

105821

646

1243

170

2750

377

683

096minus538

074

589

077

1050

148minus1056

138minus91

312

9minus78

1087

1600

219

TN-E

+SV

103551

440

283

033

887

122

655

081minus483

057

586

073

1003

124minus685

085minus719

089minus72

4090

1229

145

Note119899the

numbero

fmeasuredsamplesM

ean(119883

)averagev

alue

ofmeasurements

SDstand

arddeviation






0

5

10

15

20

25

Con

trol

PV SV

CCA+

PV

AD

-KD5+

PV

TN-E

+PV

CCA+

SV

AD

-KD5+

SV

TN-E

+SV







Table4Th

ecolor

changeso

fScotspine

before

andaft

ernaturalw

eathering

nBe

fore

naturalw

eathering

Afte

r3-m

onth

naturalw

eathering

Afte

r6-m

onth

naturalw

eathering

La

bΔL

Δa

Δb

ΔE

ΔL

Δa

Δb

ΔE

Mean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDCon

trol

107052

931

652

083

2781

423minus2149

327

425

054

222

027

2202

282minus3007

427minus426

052minus132

169

3315

491

PV10

7885

1009

766

088

3236

447minus1371

189

584

085

592

064

1603

152minus2365

326minus17

018minus884

102

2531

367

SV10

7544

1101

741

086

3256

378minus1283

149

581

065

434

037

1474

171minus2101

243minus43

037minus685

079

2251

297

CCA+PV

10712

1082

625

080

2950

360minus1212

131

412

057

521

048

1382

181minus1849

226minus119

011minus384

049

1892

261

AD-K

D5+PV

107394

909

835

130

4124

548minus1117

163

511

080

567

064

1353

130minus1746

232minus18

8021minus526

082

1833

286

TN-E

+PV

104502

518

431

059

1249

151minus737

089

355

049

592

054

1010

141minus824

103minus643

059minus595

094

1203

166

CCA+SV

107098

802

696

083

2851

294minus1039

117

528

063

795

066

1411

168minus1737

196minus564

047minus621

074

1929

230

AD-K

D5+SV

107282

954

861

118

4206

593minus1017

143

354

048

776

086

1327

182minus1588

224minus368

041minus634

087

1753

240

TN-E

+SV

104771

592

326

038

1586

197minus624

077

298

035

765

095

1031

122minus1134

141minus637

079minus585

069

1426

168

Note119899the

numbero

fmeasuredsamplesM

ean(119883

)averagev

alue

ofmeasurements

SDstand

arddeviations


0

5

10

15

20

35

30

25

Con

trol

PV SV

CCA+

PV

AD

-KD5+

PV

TN-E

+PV

CCA+

SV

AD

-KD5+

SV

TN-E

+SV






4 Conclusions









References



























































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials






WhiteL = 100

Green

Blue

BlackL = 0

Yellow

Red

+a

+bminusa

minusb



Δ119886lowast

= 119886119891

lowast

minus 119886119894

lowast

Δ119887lowast

= 119887119891

lowast

minus 119887119894

lowast

Δ119871lowast

= 119871119891

lowast

minus 119871119894

lowast

(Δ119864lowast

) = ((Δ119886lowast

)2

+ (Δ119887lowast

)2

+ (Δ119871lowast

)2

)

12

(2)








CCA 4 327 276AD-KD5 4 307 231TN-E 4 355 288






Table3Th

ecolor

changeso

fOrie

ntalbeechbefore

andaft

ernaturalw

eathering

nBe

fore

naturalw

eathering

Afte

r3-m

onth

naturalw

eathering

Afte

r6-m

onth

naturalw

eathering

La

bΔL

Δa

Δb

ΔE

ΔL

Δa

Δb

ΔE

Mean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDCon

trol

106230

760

1078

138

2178

301minus98

414

0minus98

312

699

413

11710

260minus1935

255minus123

187minus863

105

2450

314

PV10

6807

735

1260

120

2704

419

892

123minus537

062

936

120

1400

193minus1478

189minus96

613

3minus1007

109

2033

234

SV10

6354

546

1274

148

2811

371

787

083minus565

066

845

123

1286

149minus1318

192minus1016

118minus97

5084

1929

224

CCA+PV

106053

557

1215

156

2851

393

778

095minus353

045

825

125

1188

145minus1363

207minus78

5096minus753

069

1744

241

AD-K

D5+PV

105427

613

1477

142

2873

448

760

101minus339

053

726

089

1104

147minus1135

140minus94

112

5minus518

059

1563

244

TN-E

+PV

103869

352

314

043

1006

139

586

071minus397

055

695

077

992

120minus587

065minus681

082minus695

063

1136

157

CCA+SV

106146

510

1190

142

2896

489

692

078minus548

065

584

066

1058

120minus1302

147minus886

091

873

072

1801

214

AD-K

D5+SV

105821

646

1243

170

2750

377

683

096minus538

074

589

077

1050

148minus1056

138minus91

312

9minus78

1087

1600

219

TN-E

+SV

103551

440

283

033

887

122

655

081minus483

057

586

073

1003

124minus685

085minus719

089minus72

4090

1229

145

Note119899the

numbero

fmeasuredsamplesM

ean(119883

)averagev

alue

ofmeasurements

SDstand

arddeviation






0

5

10

15

20

25

Con

trol

PV SV

CCA+

PV

AD

-KD5+

PV

TN-E

+PV

CCA+

SV

AD

-KD5+

SV

TN-E

+SV







Table4Th

ecolor

changeso

fScotspine

before

andaft

ernaturalw

eathering

nBe

fore

naturalw

eathering

Afte

r3-m

onth

naturalw

eathering

Afte

r6-m

onth

naturalw

eathering

La

bΔL

Δa

Δb

ΔE

ΔL

Δa

Δb

ΔE

Mean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDCon

trol

107052

931

652

083

2781

423minus2149

327

425

054

222

027

2202

282minus3007

427minus426

052minus132

169

3315

491

PV10

7885

1009

766

088

3236

447minus1371

189

584

085

592

064

1603

152minus2365

326minus17

018minus884

102

2531

367

SV10

7544

1101

741

086

3256

378minus1283

149

581

065

434

037

1474

171minus2101

243minus43

037minus685

079

2251

297

CCA+PV

10712

1082

625

080

2950

360minus1212

131

412

057

521

048

1382

181minus1849

226minus119

011minus384

049

1892

261

AD-K

D5+PV

107394

909

835

130

4124

548minus1117

163

511

080

567

064

1353

130minus1746

232minus18

8021minus526

082

1833

286

TN-E

+PV

104502

518

431

059

1249

151minus737

089

355

049

592

054

1010

141minus824

103minus643

059minus595

094

1203

166

CCA+SV

107098

802

696

083

2851

294minus1039

117

528

063

795

066

1411

168minus1737

196minus564

047minus621

074

1929

230

AD-K

D5+SV

107282

954

861

118

4206

593minus1017

143

354

048

776

086

1327

182minus1588

224minus368

041minus634

087

1753

240

TN-E

+SV

104771

592

326

038

1586

197minus624

077

298

035

765

095

1031

122minus1134

141minus637

079minus585

069

1426

168

Note119899the

numbero

fmeasuredsamplesM

ean(119883

)averagev

alue

ofmeasurements

SDstand

arddeviations


0

5

10

15

20

35

30

25

Con

trol

PV SV

CCA+

PV

AD

-KD5+

PV

TN-E

+PV

CCA+

SV

AD

-KD5+

SV

TN-E

+SV






4 Conclusions









References



























































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




Table3Th

ecolor

changeso

fOrie

ntalbeechbefore

andaft

ernaturalw

eathering

nBe

fore

naturalw

eathering

Afte

r3-m

onth

naturalw

eathering

Afte

r6-m

onth

naturalw

eathering

La

bΔL

Δa

Δb

ΔE

ΔL

Δa

Δb

ΔE

Mean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDCon

trol

106230

760

1078

138

2178

301minus98

414

0minus98

312

699

413

11710

260minus1935

255minus123

187minus863

105

2450

314

PV10

6807

735

1260

120

2704

419

892

123minus537

062

936

120

1400

193minus1478

189minus96

613

3minus1007

109

2033

234

SV10

6354

546

1274

148

2811

371

787

083minus565

066

845

123

1286

149minus1318

192minus1016

118minus97

5084

1929

224

CCA+PV

106053

557

1215

156

2851

393

778

095minus353

045

825

125

1188

145minus1363

207minus78

5096minus753

069

1744

241

AD-K

D5+PV

105427

613

1477

142

2873

448

760

101minus339

053

726

089

1104

147minus1135

140minus94

112

5minus518

059

1563

244

TN-E

+PV

103869

352

314

043

1006

139

586

071minus397

055

695

077

992

120minus587

065minus681

082minus695

063

1136

157

CCA+SV

106146

510

1190

142

2896

489

692

078minus548

065

584

066

1058

120minus1302

147minus886

091

873

072

1801

214

AD-K

D5+SV

105821

646

1243

170

2750

377

683

096minus538

074

589

077

1050

148minus1056

138minus91

312

9minus78

1087

1600

219

TN-E

+SV

103551

440

283

033

887

122

655

081minus483

057

586

073

1003

124minus685

085minus719

089minus72

4090

1229

145

Note119899the

numbero

fmeasuredsamplesM

ean(119883

)averagev

alue

ofmeasurements

SDstand

arddeviation






0

5

10

15

20

25

Con

trol

PV SV

CCA+

PV

AD

-KD5+

PV

TN-E

+PV

CCA+

SV

AD

-KD5+

SV

TN-E

+SV







Table4Th

ecolor

changeso

fScotspine

before

andaft

ernaturalw

eathering

nBe

fore

naturalw

eathering

Afte

r3-m

onth

naturalw

eathering

Afte

r6-m

onth

naturalw

eathering

La

bΔL

Δa

Δb

ΔE

ΔL

Δa

Δb

ΔE

Mean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDCon

trol

107052

931

652

083

2781

423minus2149

327

425

054

222

027

2202

282minus3007

427minus426

052minus132

169

3315

491

PV10

7885

1009

766

088

3236

447minus1371

189

584

085

592

064

1603

152minus2365

326minus17

018minus884

102

2531

367

SV10

7544

1101

741

086

3256

378minus1283

149

581

065

434

037

1474

171minus2101

243minus43

037minus685

079

2251

297

CCA+PV

10712

1082

625

080

2950

360minus1212

131

412

057

521

048

1382

181minus1849

226minus119

011minus384

049

1892

261

AD-K

D5+PV

107394

909

835

130

4124

548minus1117

163

511

080

567

064

1353

130minus1746

232minus18

8021minus526

082

1833

286

TN-E

+PV

104502

518

431

059

1249

151minus737

089

355

049

592

054

1010

141minus824

103minus643

059minus595

094

1203

166

CCA+SV

107098

802

696

083

2851

294minus1039

117

528

063

795

066

1411

168minus1737

196minus564

047minus621

074

1929

230

AD-K

D5+SV

107282

954

861

118

4206

593minus1017

143

354

048

776

086

1327

182minus1588

224minus368

041minus634

087

1753

240

TN-E

+SV

104771

592

326

038

1586

197minus624

077

298

035

765

095

1031

122minus1134

141minus637

079minus585

069

1426

168

Note119899the

numbero

fmeasuredsamplesM

ean(119883

)averagev

alue

ofmeasurements

SDstand

arddeviations


0

5

10

15

20

35

30

25

Con

trol

PV SV

CCA+

PV

AD

-KD5+

PV

TN-E

+PV

CCA+

SV

AD

-KD5+

SV

TN-E

+SV






4 Conclusions









References



























































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials








0

5

10

15

20

25

Con

trol

PV SV

CCA+

PV

AD

-KD5+

PV

TN-E

+PV

CCA+

SV

AD

-KD5+

SV

TN-E

+SV







Table4Th

ecolor

changeso

fScotspine

before

andaft

ernaturalw

eathering

nBe

fore

naturalw

eathering

Afte

r3-m

onth

naturalw

eathering

Afte

r6-m

onth

naturalw

eathering

La

bΔL

Δa

Δb

ΔE

ΔL

Δa

Δb

ΔE

Mean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDCon

trol

107052

931

652

083

2781

423minus2149

327

425

054

222

027

2202

282minus3007

427minus426

052minus132

169

3315

491

PV10

7885

1009

766

088

3236

447minus1371

189

584

085

592

064

1603

152minus2365

326minus17

018minus884

102

2531

367

SV10

7544

1101

741

086

3256

378minus1283

149

581

065

434

037

1474

171minus2101

243minus43

037minus685

079

2251

297

CCA+PV

10712

1082

625

080

2950

360minus1212

131

412

057

521

048

1382

181minus1849

226minus119

011minus384

049

1892

261

AD-K

D5+PV

107394

909

835

130

4124

548minus1117

163

511

080

567

064

1353

130minus1746

232minus18

8021minus526

082

1833

286

TN-E

+PV

104502

518

431

059

1249

151minus737

089

355

049

592

054

1010

141minus824

103minus643

059minus595

094

1203

166

CCA+SV

107098

802

696

083

2851

294minus1039

117

528

063

795

066

1411

168minus1737

196minus564

047minus621

074

1929

230

AD-K

D5+SV

107282

954

861

118

4206

593minus1017

143

354

048

776

086

1327

182minus1588

224minus368

041minus634

087

1753

240

TN-E

+SV

104771

592

326

038

1586

197minus624

077

298

035

765

095

1031

122minus1134

141minus637

079minus585

069

1426

168

Note119899the

numbero

fmeasuredsamplesM

ean(119883

)averagev

alue

ofmeasurements

SDstand

arddeviations


0

5

10

15

20

35

30

25

Con

trol

PV SV

CCA+

PV

AD

-KD5+

PV

TN-E

+PV

CCA+

SV

AD

-KD5+

SV

TN-E

+SV






4 Conclusions









References



























































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




Table4Th

ecolor

changeso

fScotspine

before

andaft

ernaturalw

eathering

nBe

fore

naturalw

eathering

Afte

r3-m

onth

naturalw

eathering

Afte

r6-m

onth

naturalw

eathering

La

bΔL

Δa

Δb

ΔE

ΔL

Δa

Δb

ΔE

Mean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDMean

SDCon

trol

107052

931

652

083

2781

423minus2149

327

425

054

222

027

2202

282minus3007

427minus426

052minus132

169

3315

491

PV10

7885

1009

766

088

3236

447minus1371

189

584

085

592

064

1603

152minus2365

326minus17

018minus884

102

2531

367

SV10

7544

1101

741

086

3256

378minus1283

149

581

065

434

037

1474

171minus2101

243minus43

037minus685

079

2251

297

CCA+PV

10712

1082

625

080

2950

360minus1212

131

412

057

521

048

1382

181minus1849

226minus119

011minus384

049

1892

261

AD-K

D5+PV

107394

909

835

130

4124

548minus1117

163

511

080

567

064

1353

130minus1746

232minus18

8021minus526

082

1833

286

TN-E

+PV

104502

518

431

059

1249

151minus737

089

355

049

592

054

1010

141minus824

103minus643

059minus595

094

1203

166

CCA+SV

107098

802

696

083

2851

294minus1039

117

528

063

795

066

1411

168minus1737

196minus564

047minus621

074

1929

230

AD-K

D5+SV

107282

954

861

118

4206

593minus1017

143

354

048

776

086

1327

182minus1588

224minus368

041minus634

087

1753

240

TN-E

+SV

104771

592

326

038

1586

197minus624

077

298

035

765

095

1031

122minus1134

141minus637

079minus585

069

1426

168

Note119899the

numbero

fmeasuredsamplesM

ean(119883

)averagev

alue

ofmeasurements

SDstand

arddeviations


0

5

10

15

20

35

30

25

Con

trol

PV SV

CCA+

PV

AD

-KD5+

PV

TN-E

+PV

CCA+

SV

AD

-KD5+

SV

TN-E

+SV






4 Conclusions









References



























































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




0

5

10

15

20

35

30

25

Con

trol

PV SV

CCA+

PV

AD

-KD5+

PV

TN-E

+PV

CCA+

SV

AD

-KD5+

SV

TN-E

+SV






4 Conclusions









References



























































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials







References



























































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




























CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials



research article the effects of natural weathering on

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